Anthony Santander's rehab assignment hit a new snag: lower back discomfort.

He won't play tonight with Triple-A Buffalo as a result.

There's a genuinely uneasy detail attached to this update. The same thing reportedly happened last year during a different stretch of his time with the organization.

That kind of recurrence is exactly what worries a team trying to plan around a player's return timeline.

Santander has already dealt with a lengthy absence this season following left shoulder surgery back in February, an injury that kept him out of every Blue Jays game in 2026 until this rehab assignment began.

He'd shown real signs of progress recently, including a hard-hit single and his first defensive action in the outfield during this same rehab stint.

A back issue now, even a seemingly minor one, threatens to slow that momentum right when things had started looking up.

Why this specific pattern deserves real caution

Back discomfort recurring in a similar fashion to a prior incident isn't something a medical staff typically brushes off as unrelated.

Toronto will need to monitor this closely before deciding on next steps, whether that means a delay in his rehab schedule or something more involved.

There's no word yet on how serious this current discomfort actually is, or whether it changes his target return timeline in any meaningful way.

For a Blue Jays team deep in the wild-card race, Santander's potential return has represented a real power boost this offense has needed all season.

Every additional delay in that process, especially one tied to a recurring issue, adds genuine uncertainty to whether he actually gets back before the season ends.

Whether this turns out to be a minor hiccup or something more serious will likely become clearer over the next few days.