There wasn’t much information on Owen Kellington when the Pittsburgh Pirates drafted him in the fourth round in 2021. What was known was that he put up eye-popping numbers in Vermont as a prep player.
In 49 innings pitched, Kellington posted a 0.22 ERA and struck out 133 batters — good for 24.4 per nine innings.
Of course, with Vermont not being a hotbed for baseball, those numbers might not have painted a strong pitcher as to what Kellington was as a prospect.
Now in his second full season in the organization, first in Single-A, one look at him on the mound and you can see where those strikeout numbers came from.
Kellington is not going to overpower you with the fastball (average velocity currently is 90.1 mph), but his curveball is already looking like it could be among the best in the system, and evidence is beginning to mount up to prove that.
This year, Baseball Savant has been posting statcast numbers for both Triple-and-Single-A games, allowing an analytical look at the lowest, and highest level of the minor leagues.
It just so happens that two players who have easily been in the conversation for having the best curveballs not only in the system, but in all of the minors, pitched in Triple-A this season, allowing a closer look at their respective pitch.
Quinn Priester and Mike Burrows both have had a lot of success with their curves throughout their career, and it put them both in position to be one step away from the majors. Unfortunately, Burrows was injured during a game and would eventually need Tommy John surgery, so the data on him is a little more limited. You still get an idea what makes a good curve, and how Kellington compares to those two.
Quinn Priester and Mike Burrows
The numbers that have been collected for Burrows don’t tell the whole story. Usually injuries like that don’t up and appear. It can be a little bit of a progression thing, and in hindsight there may have been some signs, but not clear ones.
Priester also hasn’t used the pitch as much as you would think, but more than enough to get some good data on it.
| Mike Burrows | Statistic | Quinn Priester |
| 12.5% | Whiff% | 33.3% |
| 15.78% | Called-Strike+Whiff% | 28.57% |
| N/A | BB% | 14.8% |
| N/A | K% | 42.8% |
| N/A | AVG | .416 |
There wasn’t enough of a sample size to get any kind of respectable readings for the last three categories from Burrows, even adding in his spring training appearances that Baseball Savant recorded.
He didn’t throw the curveball much once the season started, and actually didn’t throw it all in the game he got hurt.
For Priester, his strikeout rate has been great with the curveball, but that doesn’t mean it has been completely unhittable. Opponent’s have picked up five hits in 12 at-bats, three of those being doubles.
| Mike Burrows | Quinn Priester | |
| 79.85 mph | Velocity | 78.96 mph |
| 2802 rpm | Spin Rate | 2579 rpm |
| 52-inches | Vertical Break | 52.76-inches |
| 5.4-inches | Horizontal Break | 8.03-inches |
Burrows is known for his high spin rates, so it’s not a surprise to see an elevated number. Both have very similar vertical breaks on their respective curveballs. Both have great shape, and while the metrics don’t show it, when Burrows is healthy, he gets results with the pitch.
Owen Kellington
Now looking at the young right-handed Kellington, first let’s look at the shape of the pitch.
| Whiff% | 36.67% |
| Called-Strike plus Whiff% | 38.24% |
| BB% | 5.2% |
| K% | 36.8% |
| AVG | .167 |
What’s the most impressive part of his whiff rate is that he picked up just two on 11 swings (18%) in his season debut, but has gradually gotten better in each of his outings since. He hasn’t quite put up the strikeout rate that Priester has, but hitters are batting just .167 (3-for-18) against Kellington’s curve.
| Velocity | 77.08 mph |
| Spin Rate | 2739.75 rpm |
| Vertical Break | 56.7-inches |
| Horizontal Break | 9.66-inches |
When it comes to the shape, Kellington has a larger vertical, and horizontal break on his curveball, with a spin rate just a tad under what Burrows was averaging. The 2739-rpm spin rate would still be among the top-20 highest averaging in the majors right now, so it’s still respectable on its own.
An injury cut his 2022 season down to just 10 innings in the Florida Complex League, so getting the push up to Bradenton was somewhat a surprise.
Kellington has shown why the Pirates have continually put faith in him, and after claiming a spot in the rotation, is looking to further push his mark within the system.
Having potentially one of the better pitches in the system should only help that push forward.
