The shortstop exited in the bottom of the fifth inning with left hip tightness after grounding out in the top of the frame.
Rojas told reporters after the loss:
"When I saw him not moving out of the box, for me, it was concerning. I thought it was oblique or looked to me similar as Lindor reacted in Pittsburgh when he hit the ball to second base. He felt tightness, it locked up immediately as he was approaching the dugout. I went and talked to the trainer and saw him after the game. Right now, it's left hip tightness and we're more optimistic now about what it was, what took him out of the game and he's going to come in tomorrow for more treatment. They took a look at him and it's day-to-day as of now."
Through 99 games, the 28-year-old is slashing .243/.287/.474 with 24 home runs and 68 RBI. He's tallied six hits and three RBI in eight games since joining the Mets at the trade deadline.
New York gave up highly-touted prospect Pete Crow-Armstrong to pair Baez up the middle with his friend and fellow Puerto Rican Francisco Lindor, telling the club he'd happily move to second base to join the team. That was supposed to be the start of a thrilling reunion for the two.
"I couldn't be happier," Lindor said of the trade. "I'm going to be playing alongside a good friend of mine—a great person, a great baseball player, and somebody who's going to help us win. It can't get any better. I'm very happy. I can't wait for him to come out here and put on a show for everybody."
For the Mets, the deal provided an opportunity to bolster their lineup and defense as they look to run away with the National League East.
Now that plan is on hold for the time being.
Look for the Mets to use a combination of J.D. Davis, Jonathan Villar and Jose Peraza in Baez's place until he's able to return.