Why Bo Bichette’s Wheels Fell Off in 2022

Bo Bichette burst onto the scene in 2021, proving to be every bit the star he looked like as a prospect. His bat was dynamic, and he hit for both power and average. His defense at shortstop was passable, which was all anyone could have hoped for. He was durable, too, ranking among the league leaders in both plate appearances and defensive innings. Yet despite all that, the most exciting aspect of his game wasn’t his bat, or his glove, or his resilience; I’d argue it was his baserunning.

According to BsR, the comprehensive baserunning metric we use here at FanGraphs, the young phenom was electric on the bases. He finished with the seventh-highest BsR in baseball, ahead of names like José Ramírez, Myles Straw, and Trea Turner. Meanwhile, he ranked just 37th among qualified players in wRAA and 72nd in OAA. In other words, his value on the bases was where Bichette stood out most from the rest of the league. The metrics from other sources support this point — Baseball Reference had Bichette tied for 11th in baserunning, while Baseball Prospectus had him at 16th. Only six other players ranked among the top 20 on all three sites:

Bichette was one of 10 players to swipe 25 bags, and he was caught stealing only once. His 96% success rate was the best in baseball (min. 15 attempts). He was consistent as well, posting a positive BsR and stealing at least three bags in every month of the season. Not only that, he also had a positive score in all three components of BsR (UBR, wSB, and wGDP) every single month. As sure as the sky is blue, Bichette was outstanding on the bases in 2021. So you can see why his performance the following year came as quite a surprise.

The Blue Jays shortstop was worth -2.7 BsR this past season, a sharp drop-off to say the least. One year after ranking among the top runners in the game, he finished sandwiched between the Contreras brothers, William and Willson. In sharp contrast to his 2021 season, Bichette posted a negative BsR and was caught stealing at least once in every month. Only one player, Starling Marte, saw a steeper drop in his baserunning value, and Marte is nearly a decade older and spent much of the season playing through a groin injury.

Bichette stands out among the players on this list, and not just because I highlighted his name. For one thing, he’s the youngest, and aside from Ozzie Albies, the others are all at least three years his senior. Speed is one of the first skills to decline as a player ages, but even so, the 24-year-old isn’t at a point where that should be a concern. Second, Bichette played a full healthy season in 2022, so his low BsR isn’t the result of injury or limited playing time. Finally, he didn’t just go from good to mediocre, mediocre to bad, or bad to worse. Bichette went from elite one year to the bottom of the barrel the next. The metrics from Baseball Reference and Baseball Prospectus support this evaluation:

So, what happened? How does a young, healthy player like Bichette fall so far, so fast? The simplest explanation would be declining speed. It’s hard to believe a player born the same year as the Diamondbacks and Devil Rays could be slowing down already, but it would certainly account for his plummeting BsR. Here are the pertinent footspeed metrics from Baseball Savant:

Looking at the Statcast data, you can see Bichette got a little slower this past season. His sprint speed dropped by half a foot per second, and it took him an extra 10th of a second on average to reach first base. Neither of those are big enough changes to pick up with the naked eye, but every inch counts on a bang-bang play. On top of that, the percentile figures show a more meaningful drop-off:

Relative to the norm, Bichette’s sprint speed went from a real strength to a neutral aspect of his game, and his home to first time fell behind the pack. His 90-foot time didn’t fall quite as far, but the overall message is clear: Bichette got a little slower, and the league got faster around him. His 27.5 ft/s sprint speed this past season would have ranked in the 62 percentile in 2021 – 10 percentile points higher than it was in 2022. To put it another way, he would have needed to add 0.3 ft/s to his 2021 sprint speed to remain in the 74th percentile this year. Thus, set side by side with his fellow players, Bichette was significantly slower. Even so, footspeed doesn’t tell the full story. As the data shows, Bichette was never a speedster, nor did he suddenly become a snail. There is more to his negative BsR than the power of his own legs.

As I mentioned earlier, BsR is the combination of three component metrics: Ultimate Base Running (UBR), Weighted Stolen Base Runs (wSB), and Weighted Grounded Into Double Play Runs (wGDP). Bichette succeeded in each area two years ago and was noticeably worse in all three last season:

Ultimate Base Running

UBR measures the value a baserunner adds (or detracts) on wild pitches, passed balls, and balls in play. It estimates how much a runner affects his team’s chances of scoring by either staying put, advancing, or getting out. It’s also the one aspect of BsR in which Bichette maintained a respectable score in 2022, although his total still decreased by nearly two runs. Bichette wasn’t a bad baserunner by this metric, he simply wasn’t as good as before. He didn’t run into any more outs on the basepaths (caught stealing notwithstanding), but he failed to advance as often as in 2021:

Bases Taken (BT) is a metric from Baseball Reference that combines bases advanced on fly balls/passed balls/wild pitches/balks/cases of defensive indifference into one handy stat. The average player would have had 15 or 16 BT in as many plate appearances as Bichette, and you might expect Bichette to have even more given his .333 OBP. Yet he finished with only nine last season, a far cry from his 14 the year before. Due to limited availability of data, I can’t confirm which aspect of BT was the biggest problem, but my money is on fly balls. Tag-up opportunities are much more common than the other possibilities, and according to Baseball Prospectus, Bichette had several missed opportunities for Air Advancement Runs (AAR) last season. AAR measures how much value a runner adds on balls caught in the air; Bichette contributed +0.6 AAR in 2021 and -0.6 AAR in 2022.

Another figure that stands out is the number of times Bichette advanced from first to third on a single. In 2021, he was on first when a single was hit 35 times, and he reached third (or scored) in 34% of those opportunities. In 2022, he had 38 such chances, but he was successful only 16% of the time. The league average rate was 30%.

There are three possible explanations for why Bichette was so much worse on fly balls and singles: he was too aggressive, he wasn’t aggressive enough, or he just had fewer chances to take an extra base. There’s no clear-cut answer, but by and large, the third explanation makes the most sense. These numbers don’t take into account the quality of fly balls and singles the Blue Jays hit while Bichette was on base, and not all fly balls and singles are equally effective at moving up the runner. His numbers were so much lower than league average that I have to presume he didn’t have enough legitimate opportunities to advance. Furthermore, if Bichette had really been too aggressive, he’d have been caught on the bases more often than he was; similarly, if was he exercising extreme caution, you’d expect to see fewer outs on the bases and failed stolen bases attempts. And yet…

Stolen Bases

Bichette went from 4.0 wSB above average to 1.3 below, and it’s not hard to figure out why. In 2021, he stole 25 bags in 26 attempts, and the following year he managed just 13 in 21. His footspeed is surely a factor in this, but it can’t be the only one. So, what about the speed of the catchers he ran against? Overall, they had faster average pop times than the catchers he ran on the year before:

The eight different catchers who caught Bichette were even faster, with an average pop time of 1.94 seconds. The differences between these numbers may not seem like much, but even a few milliseconds can have an impact – especially since Bichette was a little slower, too. After all, a 10th of a second in pop time makes the difference between a great catcher and a poor one.

Beyond that, though, I think this comes back to a point I made earlier: Bichette was never a speedster, nor did he suddenly become a snail. In other words, he’s not the kind of player you’d expect to steal 25 bases in 26 chances, nor is he the kind you’d expect to get caught 40% of the time. His 2021 season represented something like his 80% percentile outcome, while his 2022 season represented something like his 20% percentile outcome. He got “lucky” one year and “unlucky” the next, and those two years happened to come back-to-back. If he’d been caught just a couple more times in 2021 and safe just a few more times in 2022, the difference wouldn’t seem nearly as notable.

Any runner who likes to steal will sometimes make a risky decision and face the consequences. Other times, he’ll do everything right but still get caught on a perfect throw. In 2022, Bichette was victim to more perfect throws than usual, and his risky decisions didn’t work out as well as they did the year before. He tried to run on Sean Murphy, and he learned why that’s a bad idea. He got a good jump on Max Stassi, but Stassi nailed him with an unusually sharp throw. A drop in speed, a boost in pop time, and some bad timing combined to make a huge difference for Bichette on the bases.

Double Plays

The line between baserunning and hitting starts to get blurry when it comes to double plays. In theory, it makes sense to count wGDP as a baserunning metric, since fast runners are better able to beat out throws. But in Bichette’s case, his wGDP didn’t drop by 2.5 runs all because of his footspeed.

In 2021, Bichette grounded into 10 double plays, the median for a qualified hitter. The next season, he more than doubled that figure, grounding into 21. Such a substantial year-over-year increase in GDP would send an economist into a tizzy, but as a baseball writer, I know exactly why it happened. The majority of double plays come on medium-hit groundballs to the batter’s pull side or up the middle. Bichette hit a ton of grounders meeting that exact description in 2022:

Of the 25 additional medium groundballs he hit, every single one went to the pull side or the middle. That’s 25 extra balls just asking to be converted into double plays. On top of that, Bichette came to the plate with a double play lined up 20% more often in 2022. That wouldn’t affect his wGDP, which accounts for number of opportunities, but it does explain why he grounded into so many more double plays overall.

Bo Bichette was a burden on the basepaths in 2022, and there’s no straightforward explanation as to why. Instead, a little bit of everything went wrong and the wheels fell off in response. Bichette was slower, the league was faster, and good opportunities to advance seemed less frequent than before. His good fortune on stolen bases caught up to him, and it didn’t help that he ran on a stronger group of catchers. His approach at the plate, meanwhile, led him into more double plays. Thus, Bichette has now experienced both extremes of the baserunning spectrum in his first two full seasons. I doubt he’ll ever run like he did in 2021 again, but he should be able to put the wheels back on this season.