TORONTO -- Astros designated hitter Yordan Alvarez grabbed his right side and grimaced a few times while shuffling through the visiting clubhouse at Rogers Centre following a 3-2 loss to the Blue Jays on Thursday. The slugger left the game after his first-inning at-bat with right oblique discomfort.

It’s unknown the extent of the injury or how long Alvarez may be sidelined, but Astros manager Dusty Baker didn’t exactly sound optimistic.

“We’ll re-evaluate him tomorrow,” he said. “That’s a tough blow right there. We’ve just got to regroup and try to figure out how we’re going to win some ballgames and get through this.”

Alvarez said he felt oblique soreness on his final swing in the batting cage before the game and then aggravated it when he swung and missed twice in his first-inning at-bat against Jays starter José Berríos. He grounded out to first base and was removed from the game.

Alvarez entered the game having reached base safely in 19 consecutive games and leading the Major Leagues with 55 RBIs. He had started 36 consecutive games after missing four games with neck stiffness.

“Yordan is a key piece in the lineup,” shortstop Jeremy Peña said. “Not just in the lineup, but in general to this team. To see him leave the game early, it’s never a good thing.”

Astros second baseman Jose Altuve suffered a mild oblique injury on a swing on June 2 and missed the next four games. Altuve returned to the lineup Wednesday, and the Astros can only hope Alvarez returns that quickly.