Mason Thompson has turned many heads early this season, and it’s understandable why. Prior to this season, Thompson was a hard-throwing sinkerballer who walked a few too many batters and did not get a lot of strikeouts. After some changes, he has become a player who could pitch meaningful innings on a contending Nationals team.

Over the past three seasons, his sinker velocity has continued to drop, going from 96.2 to 94.1 mph. That is not necessarily a cause for concern though. This drop in velocity has come hand in hand with increased vertical movement, or drop, on the pitch. This led to hitters getting under the pitch more, while not giving up much exit velocity.

While this isn’t necessarily a positive change, it could lead to more line drives and fly balls, which tend to hit more often than grounders, and it has not hurt him yet.

One change that has certainly been positive is the diversification of his repertoire. When he broke into the league he threw his sinker over 80% of the time. While that could be a great thing if Thompson had the best sinker in the league, he does not.

The changes in 2022 were small. He reduced how much he threw his four-seam and changeup. He increased his slider usage to 23.9%, which all in all, only reduced his sinker usage to 72.8%.

This was a step forward. He got more whiffs on the pitch and better batted-ball results. Then he got more drastic.

Thompson ditched his changeup, in favor of a curveball. The pitch has only been thrown eight times, but it has already generated more whiffs than his changeup. The pitch brings more variation to an arsenal that was previously sitting exclusively in the mid-90s and 80s.

This comes with further increased usage of the slider, as well as an increase in four-seam usage. This diversified repertoire gives Thompson more options to confuse hitters while lacking that elite pitch.

The biggest improvement has been his strike-throwing ability. He’s thrown first-pitch strikes 70.8% of the time this season after his three-inning save against the Mets last night, far above his career norm of 57.8% and MLB’s average of 60.8%.

This has obviously allowed him to get ahead of hitters more, which has gotten him more outs.

But the biggest and more impactful change is his walks.

Last year he was just barely below league average in limiting the free pass, but so far this season he’s one of the best. His 1.5% walk rate is 99th percentile.

The importance of Mason Thompson throwing a first-pitch strike was just talked about in Mark Zuckerman’s article on MASN, but there is another strike zone-related stat there. He’s also seeing a similar trend in his zone swing percentage.

That is a positive trend in called strikes no matter how you look at it, which further allows for him to climb into a pitcher’s count.

While it is still a small sample size, Thompson’s early success is a positive sign for Rizzo and an early success for the rebuild.