Remember when Cavan Biggio first joined the Blue Jays?

The infielder’s first 160 games across the 2019 and 2020 seasons were special. In that stretch, Biggio hit 24 homers, stole 20 bases, posted a .368 OBP and was a 16% better-than-average hitter.

Then, things fell apart. Biggio hit as many homers in those first 160 games as he’s hit since. He never reached double-digit dingers again, never posted an above-average hitting season, and never earned back regular playing time. Now, Biggio is a Dodger.

So, what happened?

Let’s get the injuries out of the way early here because they are a part of Biggio’s Blue Jays story. In four seasons since Biggio’s 2019/20 breakout, the 29-year-old has dealt with hand, back, neck, and shoulder injuries causing him to hit the IL three separate times. He’s begun the last two seasons with persistent shoulder tendinitis that has become a regular maintenance issue, flaring up at times.

The injuries didn’t help Biggio, but they’re not why the infield/outfielder fell off so hard after an initial breakout. That was the league adjusting.

In his first two seasons in MLB, Biggio saw fastballs in the zone at about a 51.8% clip. In the next two seasons, that rate rose to 57.5% and 60.9% — where it’s hovered since. Biggio’s biggest strength has always been not swinging at pitches outside the zone, so teams stopped giving them to him.

The easy solution would’ve been to crush those pitches (mainly fastballs) in the zone, but that’s been Biggio’s issue. The infielder’s run value against fastballs in 2021 was -9, one of the worst marks in baseball. He’s never posted a hard-hit rate on fastballs above 36.5% since his rookie season and it’s cratered to 26.9% in 2024 — which ranks 193^rd of 222 players with at least 100 plate appearances this year.

The percentage of pitches Biggio sees in the zone has gone up every year since he cracked the big leagues. Teams built a book on Biggio and he’s been chasing an adjustment ever since.

We’ve seen brief glimpses of an approach change. By “swinging down” on the ball in the second half of last year, the infielder said he was able to ‘cover more of the plate’ and stay on the ball. A look at the box scores showed it worked, as Biggio posted a .404 on-base percentage and .765 OPS in the back half of 2023.

But that change wasn’t buoyed by some new-found production against in-zone fastballs. It was a month-long hot streak against breaking balls. Biggio’s second half of 2023 was just an incredible September where he posted a .408 OBP and .781 OPS. And that September came on the back of a 50% hard-hit rate against breaking balls. So, when teams returned to serving him heaters to start 2023, the hot streak ended.

Biggio’s 2019 and 2020 were lightning in a bottle. Teams weren’t challenging him in the zone, allowing the rookie to flash his elite eye. They weren’t feeding him as heavy of a fastball diet, allowing him to see more offspeed and breaking pitches — the ones he’s better at driving. And he even hit the fastballs in the zone better than he ever has since.

But, as is the story for so many early MLB success stories, the league adjusted. Maybe Biggio finally finds the adjustment that turns things back in his favour, but it won’t come with the Blue Jays.