Charlie Culberson has elite average spin rate
When the Braves and Rangers used Culberson on the mound in mop-up duty, Culberson flashed signs that he wasn't your average position player on the mound.
In his first career game, he showed off a 92.2 MPH fastball with above-average spin. He said after the game that he could do better if he was in shape.
One year later, he picked up his first MLB strikeout with fastballs with an even higher spin rate and a slider/curveball with an elite spin rate that dotted the zone and froze Manuel Margot.
That spin rate was at a 2019 Max Scherzer level, a pitcher who finished third in Cy Young voting and who helped lead his team into a World Series victory.
Culberson, of course, never pitched at the major league level on a regular basis, but his average fastball spin rate sat around 2400 every time he pitched.
This season in AAA, the average spin rate on his fastball was 2489 on 68 pitches. This would have tied him with Tampa Bay Rays pitcher Tyler Glasnow for 45th in MLB among 700 pitchers who threw at least one fastball and 25 pitches (aka 94th percentile fastball spin rate).
Culberson first pitched in April, when he was still a position player and his fastball topped out at 89.4 MPH. In the three games he pitched after converting, it topped out at 93.6 and averaged 91.5.
His slider, which he seldom used in the majors in mop-up duty, is also very impressive. The average spin rate is 2608 on 21 sliders thrown. This would put him at 93rd in the majors (84th percentile), in front of guys like Seth Lugo, Justin Verlander, and Adbert Alzolay, among many others.
Simply put, Culberson isn't someone at the end of his career pulling a Hail Mary hoping to extend his shelf life. He actually has MLB-level stuff.