MILWAUKEE -- A million things were going through Astros manager AJ Hinch’s mind when he was making the long and nerve-wracking run to dead center field at the end of the fifth inning Tuesday at Miller Park. His All-Star outfielder, George Springer, was lying on the ground after making a terrific catch and hitting his head on the outfield wall.

Springer grabbed his head as his teammates, a trainer and eventually Hinch surrounded him. He never lost consciousness, according to fellow outfielder Josh Reddick, and was on the ground for a few minutes before being carted off the field while sitting upright. Hinch said following a 4-2 loss to the Brewers that Springer is day to day and being evaluated for a head injury. On Thursday, the Astros said Springer was diagnosed with a mild concussion.

“He’s doing OK,” Hinch said. “He ran into the wall and obviously got carted off the field, but he’s doing well given all the circumstances of running into a wall. He made a great catch. Scary for all of us. We get out there and looks like he’ll be day to day.”

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Hinch said Springer was scheduled to fly back to Houston with the team late Tuesday night. The Astros are off Wednesday before opening a four-game series against Seattle on Thursday. Springer was unavailable while he was put through a “gauntlet of tests,” Hinch said.

“I didn’t know what it was -- could be shoulder, could be head, could be back, could be ankle, could be anything,” Hinch said. “We get out there with [head athletic trainer] Jeremiah [Randall] and I and half the team. Those are always really scary. Your mind starts racing as to what it could be. Then you just kind of have to wait for the medical evaluation.”

Springer ran back to chase a fly ball off the bat of Ryan Braun and reached up to make a catch while falling backward. It appeared Springer might have thought he was closer to the wall than he actually was and prepared himself for impact shortly after catching the ball. Instead, he landed on the warning track on his right foot and fell to the ground, with his head hitting the bottom of the padded wall.

“It was kind of weird, because it was a tough spot and I don’t think he really heard me or Mike [Brantley] yelling he had room,” said Reddick, who was in right field. “He went about it the best he could, and when he came down, all his momentum and his weight came down on kind of his lower back and his head hit the bottom of the wall and kind of jutted his head forward. He got a little bit of a whiplash, it looked like from my angle. Maybe he wedged himself into that gap under the wall, so that’s probably what caused him to have that headache kind of feeling.”

Reddick said Springer was alert and answering questions from Randall.

“He kept saying he had a headache,” Reddick said. “That was a positive sign. He wasn’t dizzy. No memory loss out there. He made sure he answered all the questions right. It was definitely a scary moment for a guy like George Springer, especially a guy with a presence in the top of the lineup like he brings. I think if he had the chance, he’d do it all over again to make the play, and we tip our cap to him for that.”

The acrobatic catch was lauded by Brewers manager Craig Counsell.

“It was a great catch,” he said. “I haven’t seen replays, but he obviously went down very awkwardly and scary. I was glad he was able to get up and was able to kind of get off under his own power, but it was very scary.”

Springer was on the injured list briefly in 2015 after suffering a concussion that happened when he made a catch while running full speed into the right-field wall at Minute Maid Park.

Springer, the Astros’ leadoff hitter, is hitting .297 with 30 homers and 78 RBIs in 105 games this season. He missed 27 games earlier this year with a strained left hamstring. Kyle Tucker, the Astros’ top-ranked prospect according to MLB Pipeline who was called up Monday, took over for Springer and led off the sixth inning by grounding out.

“It was bad,” said Astros starting pitcher Zack Greinke, who gave up a three-run homer to Eric Thames to cap a four-run third inning for the Brewers. “I was just hoping it’s nothing serious because a lot of things can go wrong when that stuff happens. Not a good feeling really.”