Alec Bohm entered the season as arguably the most highly regarded position-player prospect the Phillies have had since Dominic Brown over a decade ago.

Since his collegiate days at Wichita State, Bohm has been lauded for his advanced hit tool, power to all fields and excellent zone control, all of which led him to be selected third overall in the 2018 MLB Draft.

In 44 games as a rookie last season, Bohm hit .338/.400/.481 on his way to finishing in second place for National League Rookie of the Year. He looked primed to become one of the top young hitters in the sport in 2021.

So far in his second season though, the results have been vastly underwhelming. Through his first 45 games in 2021, he’s posted a pedestrian slash line of .225/.254/.337 and he has been worth -0.2 WAR, per FanGraphs.

Forty-five games are obviously a tiny sample size, and Bohm still has yet to accumulate even close to enough games to equal a full major league season. Bohm also isn’t alone in his offensive struggles. The MLB league average (.236) and strikeout rate (24.1%) is currently on pace to be the worst single-season average in the history of the sport.

Still, Bohm’s sharp decline since his lasting first impression a year ago has been eye-opening. His struggles have been particularly strange given that he has been very similar or better than last year in some of the advanced metrics used to predict hitters’ success.

Bohm’s barrel rate, sweet spot rate, average launch angle, whiff rate and chase rate are all basically identical to what they were last season. Additionally, Bohm’s average exit velocity has increased by 2.5 mph in 2021 to 92.7 mph, which ranks in the 92^nd percentile among MLB hitters. His hard-hit rate has also jumped by 4% since last season and ranks in the 87^th percentile among MLB hitters.

So, what gives?

Arguably Bohm’s biggest problem in 2021 has been that he’s making contact on fewer pitches in the strike zone even though he’s seeing nearly the same rate of pitches thrown in the zone as last year. Bohm is swinging at strikes nearly 5% more often than he did in 2020, but he’s making contact on such pitches nearly 6% less often.

Bohm has never walked at a high rate, but his deterioration in the above area has caused his walk rate to plummet all the way to 4.4%, which ranks 141^st among 156 qualified hitters. Of course, that’s also caused his strikeout rate to skyrocket to 27.6%, which is the 29^th highest in the league, right behind Giancarlo Stanton. That all helps explain why Bohm’s on-base percentage is all the way down to .254 this season.

Perhaps, it’s as simple as struggling to adjust to the increased velocity from pitchers all around the league. Pitchers are throwing Bohm roughly the same percentage of fastballs as they did in 2020, but the average velocity he's seeing on such pitches has increased by 1.2 mph. Bohm is whiffing on fastballs in the strike zone 8.6% more often than he did last season.

Overall, only 21 hitters have seen a worse year-over-year change in making contact on all pitches in the zone than Bohm has.

That has likely caused some frustration on his end. Bohm doesn’t swing at a ton of pitches out of the zone (63^rd percentile), but he has been chasing more pitches as of late.

He is clearly pressing a bit as the results have declined this season. It is common for young hitters to get a bit overaggressive during slumps. Bohm is basically still a rookie and some growing pains were inevitable no matter how well he started his career.

Still for a player who had been consistently regarded for his advanced zone control throughout his time in the minor leagues, the erosion in this area has been staggering.

This idea is best illustrated by Bohm's difference between last year and this year in Statcast’s swing/take metric. Swing/take divides the area over the plate into four different attack regions (heart, shadow, chase, waste). The two charts below show the frequency of pitches seen, as well as the rate of swinging or taking in that region. Every pitch is then assigned a run value based on its outcome (ball, strike, homerun, etc.).

In 2020, Bohm was one of the best hitters in the league in this department, with a run value of 14, which ranked 20^th among MLB hitters.

This season, Bohm has been one of the worst hitters in the league here, with a run value of -10 that ranks sixth-worst among qualified hitters.

No hitter in baseball has seen a worse year-over-year decline in swing/take than Bohm. As shown above, he's particularly seen a drastic dropoff in run value on pitches over the heart of the plate. Bohm not only is making contact less often on pitches in the zone, but he is not taking advantage of the times pitchers throw the ball over the middle of the plate. 

Another recurring issue for Bohm has been the high number of groundballs he’s hitting. This season, he is hitting groundballs on 54% of his batted balls and has the 12^th lowest average launch angle (4.8 degrees) in the league. Both of those rates are only small regressions from last year, but he made up for it with his better plate discipline in 2020.

That has led Bohm to ground into 11 double plays already this year, and he is on pace to surpass Jim Rice’s record-setting 36 double-play season in 1984. This is happening in an era where double plays are near an all-time low across baseball. In 2020 and 2021 combined, teams are turning fewer double plays than any time since 1968.

Only 14 players in the league have hit into more groundouts than Bohm has in 2021. In an era of constant defensive shifting, it is very difficult to find success at the plate with that many groundballs. 

All of the above factors have caused Bohm’s expected batting average to plummet from .292 last year to .265 this year.

Pitchers are throwing almost the same percentage of different pitch types to Bohm in 2021, but he has struggled a lot more against fastballs and breaking balls than he did in 2020. His xBA on offspeed pitches has risen this year, but he has seen a very small sample size of only 64 of those pitches this year, compared to 470 fastballs and 194 breaking balls.

The good news for Bohm is that he is performing well below expectation right now, which suggests he’s due for an uptick in production. His xBA is .265, but his actual batting average is just .218, while his slugging percentage is .114 lower than expected. Only 20 hitters in the league have a greater difference between xSLG and SLG.

One caveat to those numbers is that the opposite happened last year when Bohm performed well above expectation. Last year, he hit .338 even though his xBA was just .285. Only 13 hitters across the majors had a greater difference between BA and xBA in 2020.

Bohm also hit .410 on balls in play last season, which was the third-highest among MLB hitters with at least 180 plate appearances. That suggests some luck was involved in his performance last season and that his regression in 2021 shouldn’t be too surprising. His BABIP is all the way down to .276 this season, which suggests that he’s had some bad luck this season. That partially helps explain why his numbers are way down despite the fact that he’s hitting the ball harder than he did last season.

Bohm still has plenty of time to get back on track in 2021, and many of his numbers suggest he’ll begin to produce soon. It’s also important to keep in mind that he still has not cracked even 90 games in the big leagues.

Bohm’s hot start last season might have created unrealistic expectations for 2021. Even so, he has performed like a below-replacement level player thus far in his second season. The Phillies may be forced to consider getting him a few at-bats in AAA to help him rediscover his old self if he doesn’t begin to bounce back.