John Schneider revealed how Vladimir Guerrero Jr.'s back issue actually started.

Guerrero left Sunday's game in the fourth inning, but the root of the problem traces back further than that specific moment.

Schneider said Guerrero aggravated his left lower back a couple games earlier making a stretch at first base.

That detail matters. This wasn't a sudden injury from one swing or one play. It built gradually from a routine defensive action days before it actually forced him out of a game.

"It was a little tight before the game," Schneider said. "So, just wanted to be careful. Hopefully he's good for tomorrow."

That's a relatively optimistic tone from the manager, treating this as a cautious, preventative pull rather than a serious setback.

Why the origin story shapes how this gets managed

Knowing the injury stemmed from a defensive stretch, rather than something during a swing, could matter for how Toronto manages his workload going forward.

A back issue tied to a specific defensive motion is often more manageable than something connected to his swing mechanics, which would directly affect his hitting.

Schneider's comment about being "careful" suggests this was as much precautionary as reactive, pulling Guerrero before things got worse rather than waiting for a bigger flare-up mid-game.

Toronto is fighting for its playoff life with very few games remaining, making even a day-to-day issue like this one carry real weight.

The hope for tomorrow is exactly that, a hope rather than a guarantee, and Guerrero's actual availability will likely depend on how the back responds overnight.

For a lineup that's needed every healthy version of Guerrero it can get, even a short pause now beats risking something worse during the season's final stretch.