Milwaukee Brewers: Diagnosing Eric Thames’ May slump

After an amazing April, Milwaukee Brewers outfielder Eric Thames fell back to earth in May. However, the home run swing seems to be returning.

Before we all became obsessed with Aaron Judge, Eric Thames was the surprise slugger of the very early stages of the 2017 season. The Milwaukee Brewers bought a real lottery ticket in Thames as he returned to MLB after spending three seasons in Korea.

Thames was an absolute superstar in the KBO, averaging 41 home runs and 127 RBI per year with a monstrous .348/.449/.719 slash line. It’s no wonder he gained quite a following there. However, the chance to return to baseball’s brightest stage was too good to pass up. Would Thames’ success in Korea translate to the U.S., where he previously posted an uninspiring .250/.296/.431 line in two seasons for the Blue Jays and Mariners?

Well, Thames wasted little time proving his doubters wrong. It was difficult to find a hotter hitter in the season’s first month. He slashed .345/.466/.810 with 11 homers and 19 RBI in 24 games in April. Perhaps he really did find something during his international journey? As balls continued flying out of the park, Thames even found himself undergoing an increasing number of “random” performance-enhancing drug tests.

Things have been much quieter since then. Since the start of May, Thames is hitting .200/.356/.389 with five home runs and 11 RBI (including this afternoon’s solo shot against the Giants). While his overall slash line on the year remains an impressive .268/.407/.587 and his 16 homers are still among the league leaders, Thames has been coasting on that otherworldly first month.

So what has been the cause of the recent slump? Have pitchers finally figured Thames out? Are his recent hamstring and calf injuries still bothering him? Or has his luck simply turned?

Each of those scenarios may play a part, but Thames was simply never going to maintain his production from the month of April. No player in baseball could. His home run frenzy was fueled by an insane 45.8 percent HR/FB (home run to fly ball) rate. Since May it has plummeted to a robust but much more conventional 14.3 percent.

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Thames wasn’t going to continue hitting nearly half of his fly balls for home runs. But he has the tools to remain a legitimate power threat. Even during his last MLB stint between 2011 and 2012 he showed some pop. With three homers in his last eight games, after enduring a 15-game homerless drought, Thames might be rediscovering his power stroke.

A reversal in BABIP (batting average on balls in play) has also played a factor. Thames benefited from a generous .360 BABIP in April, but has contended with just a .254 mark since then. If that number settles back to a league-average level, his results should improve.

Thames’ strikeout rate has risen from 22.3 percent in April to 27.1 percent from May onward, but the Brewers will be glad to see that his ability to draw walks hasn’t suffered. He worked a 17.5 walk rate in the season’s first month, and a 16.9 percent rate since then. If Thames can rein in the strikeouts a bit, it will help his case.

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The story of the 2017 season for Thames thus far has been the contrast between one incredible month and one poor one. Long-term, he’s undoubtedly somewhere in the middle, but the Brewers will hope he’s closer to the April version than May. Despite his rough go of it the past few weeks, Thames still boasts strong numbers on the year and has put himself in a good position to end the season as one of the league’s better home run bats.

Statistics courtesy of Fangraphs.