Anthony Santander has lots to prove in short order.

The Toronto Blue Jays started Santander’s clock on Tuesday, activating the 30-year-old slugger from the 60-day injured list, officially marking his return from left shoulder inflammation that had kept him away from the team since May 29.

While the power-hitting switch-hitter was active for the series opener against the Boston Red Sox, his highly anticipated return will have to wait until Wednesday, after he nearly entered as a pinch-hitter for Daulton Varsho in the ninth inning during a frustrating 4-1 loss.

Santander needs as many reps versus major league pitchers as possible. With only five games remaining, though, that doesn’t leave him much time. There’s a very short runway to execute a takeoff here, one that could drastically alter the outlook of Toronto’s scuffling offence.

The Blue Jays’ lineup, which has scored one run or less in five of the last six contests and owns the lowest slugging percentage (.239) in the majors during that span, desperately needs a spark. So, what better time to add a 44-home-run hitter back into the mix, right?

It remains to be seen if Santander can provide some instant offence for this group. Not only that, but the jury is still out on whether he can help them in October, too. Sure, he hit a pair of home runs in 10 games during his triple-A rehab assignment, slugging .469 across 38 plate appearances with Buffalo. But can he replicate those results against big-league arms?

Even if he does, how much merit can you put on such a tiny sample size? That’s a question only Toronto’s brass can answer.

The hope is that the Blue Jays can catch lightning in a bottle with Santander during this final week of the regular season. Barring a remarkable finish, however, there likely won’t be much to learn from his surface-level results over these final five games. Instead, they’ll have to dig deeper to gain a better understanding of his potential upside.

As the team evaluates Santander’s return, health will obviously be the most important box they’ll need to check off. If he’s fully recovered, it should have a positive impact on the 2024 All-Star’s average bat speed, which declined significantly prior to hitting the IL, falling from last season’s career-high (73.1 m.p.h.) to this season’s career-low (71.9 m.p.h.) — since tracking began in ’23.

We don’t have swing metrics for minor-league games (at least not yet), so there’s no telling what Santander’s average bat speed was during his triple-A rehab assignment, adding further intrigue to his minuscule sample size during this final week before the post-season begins.

Nobody should be expecting Santander to enter Vladimir Guerrero Jr. or Addison Barger territory in this regard. That’s not his game, as evidenced by his 69th percentile average bat speed from a season ago. However, swinging hard is typically conducive to hitting for power. So, if he can take a step forward compared to his earlier readings this season, it may present a pathway to starting strong for the notoriously slow starter.

Another element the Blue Jays will surely be monitoring closely is Santander’s batted-ball distribution, which heavily influences his power output. It wasn’t his slightly-above-average hard-hit rate (41.6 per cent) that made last season’s career-high in home runs possible. It was his league-leading 54.8-per-cent fly ball rate, pulling nearly a third of those batted balls from either side of the plate.

This year, however, producing fly balls has proven far more challenging. That’s seen the veteran switch-hitter’s fly ball rate plummet by nearly 10 per cent in 2025, resulting in his highest ground ball rate (36.9 per cent) since ’19.

Taking this a step further, let’s dive into Santander’s air rate for a second, which includes line drives, fly balls and pop-ups. Last season, he recorded a 69.4-per-cent clip, the highest of his career — excluding his 13-game stint as a rookie in 2017. This season, meanwhile, that figure has dropped 6.1 per cent, resulting in his lowest rate since ’19.

While Santander had been pulling balls at a higher clip than he ever had previously, producing a career-high 30.8-per-cent pull air rate, nearly three per cent higher than ’24, it wasn’t enough to overcome his increased ground-ball output.

The Blue Jays need Santander at his best before the playoffs begin. Of course, that means hitting plenty of fly balls to the pull side. During his brief rehab assignment, though, he largely did the opposite, with half of his 26 batted ball events resulting in ground balls. A small sample size, yes, but it’s an area worth monitoring moving forward.

Not to draw too many concerns from the slugger’s rehab stint, but another aspect likely worth keeping an eye on is his quality-of-contact metrics, considering he featured a less-than-inspiring 26.9-per-cent hard-hit rate at triple-A.

Toronto must also be mindful of Santander’s plate discipline. He struck out over a quarter of the time during the first two months, pushing his strikeout and whiff rates above 20 per cent for the first time since ’23. But he displayed encouraging signs in Buffalo over the past few weeks, earning as many walks as strikeouts (six) while swinging and missing just 15.6 per cent of the time.

Proving he’s 100 per cent from both sides of the plate will also be key for Santander, who’s felt more comfortable with his left-handed swing than his right-handed stroke while recovering from his shoulder injury. But from a matchup perspective, he needs to be a viable option from either side.

There’s a realistic scenario that Santander serves as an off-the-bench platoon bat for the Blue Jays this October. With several left-handed hitters already in the mix, though, including Daulton Varsho, Addison Barger, Nathan Lukes, Andrés Giménez and Joey Loperfido, chances are there’ll be more pinch-hitting opportunities for righties than lefties.

As such, the Blue Jays need to see what they have in Santander as a right-handed batter. There’ll be an opportunity to do just that on Wednesday against Red Sox ace Garrett Crochet, presenting a tough landing spot for the recovering slugger. Not an easy matchup, by any means. But it’s not like those exist in the playoffs, either.

It’s sink or swim for Santander the rest of the way. They need a bat like his in the lineup, especially given the absence of Bo Bichette, who isn’t eligible to return until Game 1 of the American League division series. At the same time, the team also has to justify playing him over someone who’s helped them reach this point in the season.

These final five games are all they have to work with, and they’ll need every piece of evidence to determine whether or not to carry Santander on their post-season roster — either in the wild-card round or ALDS. And his underlying metrics should help with that, allowing them to project his future production through a wider lens.

But there’s also a relationship element at play here. This is Year 1 of a five-year, $92.5-million contract for Santander. It shouldn’t automatically earn him a spot on Toronto’s post-season roster. Instead, management should let the results, whatever they are, speak for themselves. Still, he’s a massive part of this team’s plans beyond ’25, making for a delicate situation if he’s left off the roster.

Everything is about winning games from here on out, and if Santander’s bat proves it has the potential to win the Blue Jays a playoff game or two — or even a series — then all doubts regarding his roster status will be silenced.