BOSTON – Astros All-Star outfielder George Springer is day-to-day after leaving Sunday’s 4-3 loss to the Red Sox at Fenway Park in the fourth inning with lower back stiffness. Astros manager AJ Hinch said Springer wouldn’t play Monday’s series opener against the White Sox in Houston.

Springer, who has played in every game this season, went 0-for-3 with three strikeouts against Red Sox ace Chris Sale while starting in right field Sunday and said after the game his back stiffened up. Hinch said Springer would get a further examination Monday.

“Not necessarily ideal, but we’ll see what happens,” Springer said. “Hopefully I’ll feel better tomorrow.”

When asked how long Springer has been dealing with it, Hinch deferred to the player, who was vague.

“It’s just kind of one of those things, I felt it more and more and it’s dumb to kind of play through it,” Springer said. “Again, we’ll see what happens tomorrow and hopefully I’ll be alright.”

Springer, who entered Sunday leading the American League in OPS, homers, RBIs and runs scored, looked uncomfortable on some swings during his three at-bats against Sale. He dropped to a crouch after striking out against him in the second inning and appeared to be wincing.

Several times in the last week, including his first at-bat of Friday’s win against Boston, Springer has grabbed his lower side after swinging the bat, but Hinch has said Springer told him he was giving himself a reminder to maintain proper mechanics through his swing.

“He never really got loose today and it got progressively worse and his swings got a little more timid as the day went on,” Hinch said. “I probably should have taken him out a little earlier, too. We’ll get him evaluated when we get home.”

If Springer is out for an extended period it would be a huge blow to the Astros, who had their 10-game winning streak snapped Sunday. An early candidate for AL Most Valuable Player honors, Springer is hitting .313 with 17 homers, 42 RBIs and a 1.050 OPS and has been a catalyst at the top of the lineup.

“Any time you feel like you’re swinging the bat well, you want to stay on the field,” he said. “I want to be on the field even if I’m not swinging the bat well. It’s a little frustrating but I’m hoping I can feel good tomorrow and get back in there.”

The Astros have already been without former AL Most Valuable Player José Altuve for the past week with a left hamstring strain, though he could return within in the next week. Outfield prospect Yordan Alvarez, Houston’s No. 3 prospect per MLB Pipeline, has been crushing Triple-A pitching -- he’s hitting .411 with 18 homers, 55 RBIs and a 1.378 OPS at Triple-A Round Rock -- but the club has been hesitant to call him up.

Houston could be waiting until June to make sure he’s past the Super Two deadline, which would ensure he’s not eligible for arbitration a year early, but there are also concerns about his defense. Hinch is committed to rotating cornerstone position players like Springer (when healthy), Michael Brantley and Altuve through the DH spot, so Alvarez would have to play defense proficiently to remain in the lineup on a daily basis.

Springer played in all 162 games in 2016 but has dealt with several injuries in past seasons. He suffered a concussion and later a fractured wrist and missed two months in ‘15, spent time on the disabled list with left quad discomfort in ‘17 and missed 10 games last year when he sprained his left thumb.