JUPITER, Fla. -- Andrew Miller, who didn’t throw his relief assignment on Monday and who has been trying to get a feel for the baseball when he pitches, underwent a series of tests Tuesday morning to try to determine the reason for the different sensation.

Miller, 34, said that he has been trying to work through the issue for some time and is using Spring Training to dig deeper. He did not have an MRI on Tuesday, but he met with the Cardinals’ medical team to figure out what could be wrong. Miller began playing catch again Wednesday and will go through a few more tests, while waiting to hear back on the results of those he has already taken. Manager Mike Shildt said nothing out of the ordinary has been found on the testing that has been done so far.

The veteran left-hander apologized many times on Tuesday for not being able to describe exactly what he feels -- or doesn’t feel -- when he pitches, noting that nothing physically hurts. But something isn’t right, and he’s been trying to work through it. In his first season with the Cardinals, Miller had a 4.45 ERA, and he didn’t allow a run across six appearances in the postseason.

In his spring debut on Friday, Miller struggled with command before getting out of the inning, and on Monday, he stopped warming up after throwing at least one wild pitch.

“I know what it feels like when I’m right,” Miller said. “And I guess this is probably vague again. But the sensation I have throwing a baseball right now just isn’t consistent with what it is when I know I’m good. It’s just been a challenge.”

In addition to the testing, Miller has had his bullpen sessions analyzed with the Cardinals’ technology seen around camp this spring, including Rapsodo and Edgertronic cameras, to compare his metrics with his previous data. Miller said the issue could be as simple as adjusting his mechanics, as he’s done before. He and the Cardinals are trying to look at all the different options, including nerve-related issues, that could be causing the lack of feel.

Miller said there’s no tingling, no burning, no soreness and no clear pain in his arm. He also outlined that he’s not showing signs of carpel tunnel syndrome, which is what put Brett Cecil on the injured list last year. Nor is he showing symptoms -- like numbness in the fingers -- of thoracic outlet syndrome, which is something that a growing list of pitchers have dealt with.

But this feeling is something he’s had problems with for some time, and he and the Cardinals want to find answers this spring.

“I’ve probably been dealing with it for awhile,” Miller said. “There was no moment of pop, pull, ‘That hurt,’ or, ‘That felt weird,’ kind of thing. And then, OK, this is clear-cut, on this day I was fine, on this day I was not. It’s probably been a pretty gradual thing.”

Reyes finding command again

Alex Reyes, healthy for the first time in three years and working toward a spot in the Majors this year, struck out four in two innings of relief in Tuesday’s 6-3 win over the Astros. He allowed one run on three hits and a walk, but it was his longest outing since being shut down from throwing in July last season. Reyes threw 44 pitches, 28 of those strikes, and it was the first time he’s thrown more than an inning this spring.

“It felt good to be able to get back out there,” Reyes said. “Thought my curveball was good, was able to throw it for strikes. I thought everything was pretty good except that changeup to [Carlos] Correa. It stayed up a bit and he got a good swing on it.”

Reyes is still getting a feel for his fastball command, but he’s recovered well from the outings he’s had this spring. Now it’s about getting the stamina back to build up to a starter’s workload.

“That’s what today was for, to get back out there and throw multiple innings,” Reyes said. “Hopefully my next one will be more.”

Reyes followed starter Dakota Hudson’s four efficient innings. Hudson threw 46 pitches (29 strikes) and allowed one run on two hits, while walking one and striking out two.

Rehab roundup

• Yairo Muñoz (left hamstring strain) will have an MRI on Wednesday. The utility infielder will likely start the season on the injured list after straining his hamstring running out an infield single last week.

• Brad Miller (back stiffness) is still considered day-to-day but will likely be back in the lineup Saturday after the Cardinals’ off-day Friday. Miller was scratched Sunday in a cautionary move after feeling tightness in his lower back when hitting.

• Kwang-Hyun Kim (groin soreness) recovered well from his bullpen Monday and is scheduled to start in Thursday’s split-squad game at Roger Dean Stadium.

Up next

The Cardinals head to Port St. Lucie, Fla., to face the Mets on Wednesday at 1:10 p.m. ET. Jack Flaherty will start and throw four innings or 70 pitches, followed by Daniel Ponce de Leon's four innings or 70 pitches. Junior Fernandez is scheduled to pitch the final inning, while Kodi Whitley and others will be available to throw as well. Watch on MLB.TV or listen live on Cardinals audio.