JUPITER, Fla. -- Andrew Miller warmed up to throw in Monday’s 6-1 win over the Twins, but the veteran reliever was shut down after he “couldn’t get a feel for the baseball,” Cardinals manager Mike Shildt said.

“It’s the best and easiest way I can explain it,” Shildt said. “So we’ll evaluate it moving forward. Nothing physical as far as health, or arm. Just having trouble feeling the baseball. … I think not feeling the sensation of the baseball itself.”

Miller, 34, was a few days behind schedule this spring as he built up his workload. He made his spring debut against the Mets on Friday and had trouble finding his command when he hit two batters and walked another before getting out of the inning.

“Just kind of feeling something the last couple of times I went out,” Miller said, notably cautious when speaking about the issue. “It’s frustrating, but I feel -- physically nothing hurts.

“Honestly, I don’t even know what it is right now. Just trying to come up with some solution for it.”

Neither Miller nor the Cardinals knew what the solution would be yet on Monday. He will be evaluated over the next couple of days to find out whether or not the issue is nerve-related, and once the problem is diagnosed, there will be a better sense of a timeline for his spring.

“I can’t say it’s not a concern,” Shildt said. “I mean, it’s a concern when a player has health [issues] and is trying to figure out what it is and move forward with it. It’s a concern, I can’t tell you how grave it is, but clearly it’s something that’s going to be addressed.”

Miller has had injury problems before, most notably in 2018 with Cleveland when he went on the injured list three times with right knee, left hamstring and left shoulder issues. He’s in the second year of his two-year, $25 million contract with a team option for 2021 signed last offseason. After being signed as the high-leverage left-handed reliever with postseason experience, Miller is also being considered for the open closer spot with Jordan Hicks recovering from a right elbow injury and Carlos Martínez vying for a rotation spot.

In his first season with the Cardinals, Miller had a 4.45 ERA in 73 games and 54 2/3 innings. The Cardinals signed him one season removed from his two All-Star years in 2016 and 2017, when he had a 1.45 and 1.44 ERA, respectively.