Williams: Rodolfo Castro Has Become a Lefty Masher

We are all ultimately judged by how many things we can do in a second.

Rodolfo Castro picked up two outs in a second on Saturday.

In the third inning of game one on against the Washington Nationals, the Pirates were trying to protect a 2-0 lead. Rich Hill had loaded the bases with no outs, but got Jeimer Candelario to hit a sharp line drive to Castro at short.

Castro fielded the ball like he was relaying a double play throw. In a second, he caught the line drive and threw to second — where Mark Mathias was waiting to double off the runner for the second out.

A huge credit to both players for instantly reacting. Castro for successfully catching the line drive and instinctively going for the second out. Mathias for reacting toward second on contact to be there for the out. The awareness from both players took Washington’s win probability from 63% to 43%.

We are all ultimately judged by how many things we can do in a second.

There’s nothing more challenging to a baseball player’s split-second abilities than the ability to hit a baseball.

Castro went 2-for-5 today, picking up both hits against lefty starter Patrick Corbin. After the Pirates’ 6-3 victory in game one, Castro had a .288/.384/.479 line on the season, with three home runs in 86 plate appearances.

Castro’s progression at the plate has been gradual since the end of last season. He was starting to make better swing decisions in Triple-A over the summer, and carried that to the big leagues in August.

To get a better idea of the swing decisions Castro is making, here is a look at his swing rates from each side, via Brooks Baseball.


Castro saw 56 plate appearances as a right-hander in the majors prior to August of 2022. As you can see in the chart below, he was a free swinger. There wasn’t a pitch that Castro wouldn’t swing at in the very top of the zone, and he couldn’t lay off the bottom of the zone.

He also was swinging at a lot of outside pitches, while protecting inside balls. Castro wasn’t really focusing on any specific area of the plate with his attack approach. Keep in mind that Castro is going to be standing on the left of the images below.

Here are the numbers so far this season from the right side. I’ll let the mostly blue chart show how selective he’s being with where he’s covering the zone.

Castro still goes for those low pitches, but he’s done a great job of narrowing his swing focus to the low, outside part of the strike zone. He’s cut down swinging at extreme outside pitches, and he’s almost abandoned the top quadrant of the zone — even if it means more strikes in the top outside corner. Overall, he’s shifted his focus down, and more controlled within the strike zone.

He has a 1.248 OPS as a right-hander against lefties this year. He added two more hits today against Corbin. This has been, by far, the biggest impact to his game.

Castro had an .861 OPS against lefties in 2021, but a .600 OPS overall in 2022. He’s looking like a lefty masher in 2023.


Castro had 115 plate appearances as a lefty hitter pre-August 2022. He would be on the right side of the images below. As a lefty, he was still a free swinger — active above and below the zone, while swinging at outside pitches.

In 2023, Castro still goes for some outside pitches. He’s narrowed his focus at the top and bottom of the zone, specifically on inside pitches.

From this comparison, it looks like he’s focusing more to the top right part of the zone. It also looks like he still has some work to do to narrow his focus toward the middle.

So far this year, Castro has a 30.4% strikeout rate from the left side, which has led to a .601 OPS. He’s still got some things to improve upon from this side.


In my trip to Altoona last year, I wrote about the Pirates’ approach to hitting development, where they’re getting hitters to focus on specific areas of the zone to lay their focus.

Jon Nunnally Discusses the Hitting Development Approach in Altoona

The approach the Pirates have for their hitters is akin to a game of chess, where a hitter controls the middle of the board, then isolates their area to attack away from the middle.

“If you can control the middle of the plate, you can control the game,” said Nunnally. “They’ve got to throw strikes. We’ve just got to control that portion of the plate that if we get in there, we can hammer something.”

That approach was discussed in Altoona, but it’s a system-wide approach. As you can see with Castro above, he formerly was swinging at literally everything from the right side. He’s now narrowing his focus to a very specific area of the zone, and it’s led to a massive results. His focus hasn’t been as narrowed from the left side, which has resulted in continued swing and miss issues.

We are all ultimately judged by how many things we can do in a second.

Logically, each area of the zone would require a microsecond to defend. If you’re focused on fewer areas of the strike zone, you don’t have to spread your time focus as far. You can focus on your zone, and have more time to dismiss anything outside of that zone.

Castro seems to have found his zone from the right-side of the plate. He seems to be settling into another type of zone in the field, stepping up to replace Oneil Cruz. If he can narrow his zone from the left-side, we could see Castro emerge as an All-Star everyday starter.


**What a great debut by Miguel Andujar in game one. He went 2-for-3 with a two-run homer, breaking a 2-2 tie. If you missed it, check out Anthony Murphy’s writeup of Andujar’s hitting success from just prior to his callup.

**I was glad to see Colin Holderman getting an easy outing today, after struggling in his last appearance. With a 6-3 lead, Holderman pitched a clean inning, needing just 11 pitches, and throwing seven strikes.

**The Pirates needed this start from Rich Hill, who spared the bullpen of a short outing in the first game of a double-header. Since his first two outings, Hill’s results have been exactly what you’d hope for from a free agent meant to provide a stabilizing presence to the rotation. He kept the Pirates in the game all day, allowing for the Andujar homer to shine through.

The Pirates won game one 6-3. Jeff Reed will have a recap of both games after game two.


John Dreker broke down the latest MLB draft rankings from Baseball America.

Pirates Draft Prospects: A Look at the New Draft Rankings and Many Familiar Names

Anthony Murphy looked at the hot start to the year from Tres Gonzalez in Bradenton.

Pirates Prospects Daily: Tres Gonzalez Hitting Well In Bradenton To Start Year

Tim started Pirates Prospects in 2009 from his home in Virginia, which was 40 minutes from where Pedro Alvarez made his pro debut in Lynchburg. That year, the Lynchburg Hillcats won the Carolina League championship, and Pirates Prospects was born from Tim's reporting along the way. The site has grown over the years to include many more writers, and Tim has gone on to become a credentialed MLB reporter, producing Pirates Prospects each year, and will publish his 11th Prospect Guide this offseason. He has also served as the Pittsburgh Pirates correspondent for Baseball America since 2019. Behind the scenes, Tim is an avid music lover, and most of the money he gets paid to run this site goes to vinyl records.

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When Cruz was heathy and Castro was benched they would insert Castro for Bae at 2nd then shift Bae to CF and move JS to RF
Same scenerio but Marcano starts SS and Castro has day off

This is still exebition right? They know its not OK for them to dismantle the middle of the field with those def upgrades in a postseason game, Right? Right?


this might be wrong but could it be possible that the Pirate pitching is doing so well because the catchers are doing an outstanding job of calling the game and framing the pitchers. I do not mean to take anything away from the pitchers who have been excellent.


Dewey Robinson is the reason

Best in the business


Statcast Leaderboard xwOBA – 6 Pirates in the Top 100

#7 Jack Suwinski 109 PA .448 xwOBA
#21 Bryan Reynolds 112 PA .407 xwOBA
#34 Connor Joe 89 PA .388 xwOBA
#46 Andrew McCutchen 107 PA .375 xwOBA
#69 Ke’Bryan Hayes 115 PA .357 xwOBA
#97 Rodolfo Castro 91 PA .339 xwOBA

Santana is at #139 and Bae is at #249


It seems like his start to the season is only affirming what we already knew about Castro. His ultimate utility will be determined by putting him in positions to succeed, i.e., see Rays. I’m just hoping that Cruz’s injury doesn’t exploit his weaknesses due to the need, and lack of a legitimate alternative, for a temporary replacement at SS.


Castro has had a lot of reps at SS, but most were prior to the last two years where his play has been mostly 2B or 3B. Therefore, it took him a number of games to start to feel comfortable at SS again.

I agree with everything you have written – Rodolfo Castro has always been a free swinger – what’s that saying about kids from the DR – “can’t Walk off the Island”! After last year’s 250 AB’s he had decent numbers for a pre-Rookie, but 74 K’s and only 22 Walks was not positive. When the season ended he was told they wanted him to work on being more selective. He was not the only one – the same went out to Oneil Cruz (28 Walks, 128 K) and Jack Suwinski (41 Walks, 114 K).

Before being injured, Cruz was 7 Walks and only 8 K. Suwinski is presently 14 Walks, 22 K and Castro is 10 Walks, 22 K. Solid improvements. It also helps to have veterans like ‘Cutch showing the way with 14 Walks, 17 K, or Ke’Bryan Hayes 10 Walks, 13 K, and Carlos Santana 11 Walks, 19 K. Connor Joe is very respectable also with 11 Walks, 22 K.


RC can’t throw a baseball accurately anywhere in the diamond.
He is not the only one.

He should tbe thankful he’s playing for a FO
that clearly doesn’t care about defense.

Yep, as long he gets an XBH for every
THROW or BOOT (once every 4-5 Games) he is good to go

This your last chance kid


Cruz getting hurt was the best thing that could’ve happened for Castro. It forced him to make a mental adjustment to his role on this team. He believes he has to pick up the slack for his friend. Sometimes putting an extra burden on oneself causes diminished productivity, and other times it motivates an individual to be a better version of themselves. Obviously Castro has shown the determination to succeed.

It’s a beautiful thing to see.


Agree. Maybe Castro is applying greater focus. It just feels like he’s taking a more mature approach vs early last season.
Imo, his floor is Josh Harris-like performance, but his ceiling is much higher due to his size and athleticism.


I love Castro……like the way a father loves his son. Anyway, He has the athleticism to be an elite player. Seeing him mature and put the work into his professional development is a great thing to watch.


Great article Tim!

If you are taking article suggestions, I’d like to see a piece by you and Anthony Murphy about the changes in Tucupita’s game

To me it looks like his batted ball profile is similar to that of Ke’Bryan which is outstanding

EV and hard hit % are way up, and I don’t think it’s a small sample noise

Also it appears that his running skills have “aged”

Marcano is another guy who could be a core piece for a playoff level team


Big fan of Marcano for the same reasons Padres wouldn’t include him in the Musky deal and why later BC wasn’t giving up AF without him as part of the return.
Your starting to see a big part of his game not yet shown in the BIGS
minors career 189 BB–185 K


An interesting question I’ve wondered since the days of NFW in a Pirates uniform, is who decides, and how, if a switch hitter’s dropoff in proficiency of their weaker side is small enough that the platoon advantage/disadvantage still outweighs it. Or, put more simply, at what point is a player better off to decide (or be told?) he’s a LH (or whichever) batter?

Obviously way too early to pigeonhole Castro w/r/t handedness, but it’s just an interesting question to me in general, that this article brought back to mind. Like, for instance, you’re a switch hitter who’s a career 115 wRC+ from the left side and say an 85 from the right. If you just batted left on left, would those results be worse than the 85? What if it were 120 and 80? Etc.

If you are above average both ways, and/or the spread is small, it makes total sense. But it feels like with a large enough spread between, or a well over average side and a well under one, there’s some point where maybe it doesn’t.

Anyone have any insight on the process and/or decision?


I would like to see what he could do batting rh vs a rh pitcher, in season is tricky though. Maybe some live batting practice or the occasional at bats in game to see if he takes to it. Risky as can be though.


I’ve wondered about this too, especially because his minor league splits show the same thing. For example, in 2019 with Bradenton and Greensboro, he had a .704 OPS batting LH and a .912 OPS batting RH (if just looking at Greensboro, it was a .776/.987 split–so he hit well LH at Greensboro but still with a huge split). In 2021 with Altoona, it was a .623 vs. .748 split.


That one r on r at bat was against a position player in a blow out, so i guess that was in Colorado. I think he was trying to see if he could hit a long homer. Did not.


Thanks for chiming in. Heck, I’m sure trying to change just about anything against big league competition is an awfully large ask.

It’s probably more of a rhetorical question than anything — like where is that line where the comfort level and visual perspective that you are used to from seeing every pitcher from the optimal side (probably ever since you could hold a bat or since you were old enough that a coach got you to try it) gets trumped by an inherent skill/ability advantage from one side or the other.

I’ve never done any searching, but maybe the answer is ‘never’; maybe dropping switch hitting just isn’t done, at least not at any development level even close to the bigs. Idk how much, if any, precedent there is. Maybe that chatGTP thing can scour the net and tell me 😁


My thought is that the specific player, in this case Castro, will almost never choose to abandon being a switch hitter. On the other side of the coin the manager will always play to strengths to gain an advantage in the pitcher vs. batter matchup. So my conclusion is that what we as fans see in games is effectively a platoon bat who is a switch hitter but without any doubt Castro is putting in work as a left handed hitter on a daily basis. But while the Bucs are the best team in the NL, I say let’s platoon Castro and Bae at 2B and Suwinski and Reynolds in CF with Reynolds playing daily shifting from LF to CF when the team is facing a lefty starter and Suwinski sits. Especially with Andujar up now.


I’m sure AI could improve this answer but here’s a recent article on the topic



That’s a good question

A recent example is Cedric Mullins back in 2021



Love the article and development that Castro has made. Seems like he is really working at his craft and it is showing in the results. If he can clean it up from the left side, he’s a lock to me to take 2B long term once Cruz is back.

Thinking about Dick Mountain, I could see him passing Julio Franco as the oldest guy in the modern era to play. Not like velocity loss is a concern. As long as he can keep spinning it, teams may keep calling.


I upvoted you just for Dick Mountain! Took me a minute 🙂


Biggest concern will be staying healthy.


Good piece, Tim. Rudy’s looking more like a big leaguer this year, could be something special.


Many of the same comments at the end of NBA season, guys saying what they needed to work on. Baseball seems to be the one sport where guys have the time to work on skills.

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