The Toronto Blue Jays will be without their struggling first baseman on Monday.
Vladimir Guerrero Jr. is not in the lineup for Game 1 of the Blue Jays' three-game series against the Baltimore Orioles after exiting their game on Sunday with lower back tightness.
Guerrero was 1-for-2 with a single before being removed in the fourth inning against the Texas Rangers.
Rookie Sean Keys will play first and bat fifth in Guerrero's absence against the Orioles.
Keys has two home runs and a .644 OPS over 20 games with the Blue Jays this season. But the 23-year-old ranked as Toronto's No. 6 prospect before graduating and had 28 home runs, 80 RBIs and a 1.019 OPS between double-A and triple-A this year.
Manager John Schneider told reporters post-game on Sunday that Guerrero felt his back act up earlier in the series when stretching to field a throw at first base.
"Just being careful, really," Schneider added on why Guerrero was removed. "He hasn't complained about it much. It was a little tight before the game, so just wanted to be careful, and hopefully he's good for tomorrow."
Guerrero, 27, is in the midst of the worst season of his career at the plate, slashing .263/.336/.359 with a .695 OPS, nine homers and 56 RBIs through 140 games.
His exit came hours after the Blue Jays announced that ace Dylan Cease will miss his next start with shoulder fatigue.
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