Eric Thames knows how to hit a baseball. This fact is arguably the biggest revelation of the young 2017 MLB season. After departing from the majors in 2012 following two largely unsuccessful seasons in the big leagues, Thames headed to Korea. Back in the majors for the first time in five years, the Milwaukee Brewers first baseman has had an incredible first month of the season offensively, ranking among the league leaders across nearly all statistical measures. Thames is tied for the league-lead in home runs with 11, 10th in batting average at a strong .345 mark and tied for 17th with 19 runs batted in. He also owns baseball’s third-best on-base percentage and second-best slugging percentage, indicating that not only is he hitting for power at an elite level, but he’s also getting on base at a superstar level. This tracks with advanced metrics, as Thames ranks second in both wOBA (weighted on base average), which adjusts on-base percentage for the value of getting on base in each specific way, and wRC+ (weighted runs created plus), which shows that he has been worth the second most runs in the league, per Fangraphs.

Unfortunately, as a baseball fan, it is now impossible to see a seemingly out-of-nowhere power surge and not have the word ‘steroids’ flash in all caps in your mind. Both Major League Baseball and Eric Thames are acutely aware of this. As reported on April 29 by Milwaukee Brewers beat writer Tom Haudricourt, Thames has been drug tested by the MLB three times in what was then the last ten days. This is not normal, and certainly not random. Thames has offered to keep testing as much as the league wants, saying to the press recently after a game that, “If people keep thinking I’m on stuff, I’ll be here every day.” Given his unbelievable story and the complete inability of baseball fans to trust anyone anymore, people are going to doubt him no matter what he or the tests say. However, the nature of Thames’ success suggests that the underlying reasons for his great month might have to do more with smart hitting than a physical power surge.

Thames’ newfound success is not the case of a man who is fundamentally the same hitter as when he washed out, only now the ball flies farther and is hit harder when he makes contact. In the 2009 Baseball Research Journal, University of Illinois Physics Professor Alan Nathan supported the argument made by fellow physicist Roger Tobin that steroid use would increase muscle mass which, in turn, would result in higher bat speed and a correspondingly higher ball exit velocity from the bat. This would suggest that power-hitters using steroids would have high average exit velocities on batted balls. Thames, however, has a remarkably low average exit velocity on batted balls this season, per Statcast. His 89.79 mph average exit velocity is only slightly above the league average rate of 87.69 mph, and well below Minnesota Twins third baseman Miguel Sano’s league-leading 100.6 mph. While this is not a way to be sure, it certainly does not point toward steroids.

Rather than pure force being the difference between his past failures and current success, its possible that it is instead due in part to strategic changes in his approach at the plate. In addition to structural changes to his swing, Thames has significantly reduced the percentage of pitches he swings at (38.0 percent this year, 49.3 percent in 2012 and 50.6 percent in 2011), and in particular the percentage of first pitches that he swings at (16.2 percent in 2017, 30.2 percent in 2012 and 30.4 percent in 2011), per Baseball Reference. Additionally, he has greatly reduced the percentage of pitches outside the zone that he swings at (19.1 percent in 2017, 35.6 percent in 2012 and 36.8 percent in 2011).  

Baseball is more fun with guys and stories like Thames. Hopefully our collective cynicism about steroid use won’t completely decimate our ability as fans to enjoy what has been a truly special start to the season.