JUPITER, Fla. -- Among a series of roster moves Saturday, the Cardinals placed Yairo Muñoz on unconditional release waivers, making him a free agent after the utility infielder left camp and flew home to the Dominican Republic, leaving the Cardinals unsure when or if he would return.

“Trying to determine what’s the next best step, just decided that based on what we’re hearing from his agent, maybe cutting ties makes the most sense,” president of baseball operations John Mozeliak said. “He just wasn’t happy here, was frustrated with how he was used last year, and didn’t like the writing on the wall I think he was seeing this year.”

Muñoz, 25, had been the Cardinals' utility infielder the last two years and was vying for a spot on the 26-man roster. Last Saturday, he strained his left hamstring running out an infield single. The Cards scheduled him for an MRI on Thursday, but he never showed and never gave the team notice of his plans.

Mozeliak said that Muñoz texted a teammate, and that’s how the Cardinals learned that he flew home. The move opens a spot on the 40-man roster.

“Trying to assess where he is physically, I just don’t know,” Mozeliak said. “The bottom line is he left the club, and we can either wait this out, but I don’t feel like that’s in our best interest, because the likelihood of him coming back and being happy didn’t seem very high.”

Manager Mike Shildt called the departure “baffling,” adding that the lack of communication was unusual for Muñoz, with whom Shildt has had a good relationship since the Cardinals acquired him from Oakland in the 2017 deal that sent Stephen Piscotty to the A’s. Muñoz outperformed other bench options the last two Spring Trainings to force his way onto the Major League roster.

Shildt emphasized that his biggest concern was for Muñoz’s well-being, not for the roster spot. It was unclear Saturday whether Muñoz left solely because he was unhappy with his role.

“Really just wishing him the best, ultimately, is what I can say,” Shildt said. “Haven’t had a good chance to communicate with him, he’s just kind of gone off the grid. Lot of respect for Yairo, love the way he competes, just enjoyed the personal relationship with him, and I wish him nothing but the best.”

With his playing time staying stagnant, being used as a versatile option off the bench, Muñoz remained frustrated. Mozeliak said he heard about the disappointment from others, not from Muñoz directly. Shildt said he had conversations with Muñoz about his playing time, trying to emphasize that the decisions weren’t personal, sometimes it was just how the game developed.

“Doesn’t matter who it is, I always love the fact that our guys want more,” Shildt said. “Look, it’s their careers, they want more opportunities, I want them to believe in themselves. You hope that they can do it and understand the big picture of what that looks like. It can be a harder thing for a younger player to understand what that looks like.”

Shildt also said that Muñoz was on a track to get more playing time this year, especially with the extra spot on the roster and Muñoz once again impressing early in camp. His versatility playing all over the infield as well as the outfield put him in the competition for a utility role in St. Louis, and he was one of the leaders for early at-bats this spring before straining his hamstring.

“He was going to see more opportunities this year with our club,” Shildt said. “Again, I wish him the best and I wish I had a better explanation for you, but it’s been pretty baffling, quite honestly."

Muñoz had one more option remaining and seemed likely to spend some time in Triple-A Memphis, where he would be a starter instead of getting sporadic playing time in the Majors.

In two years with the Cardinals, Muñoz slashed .273/.331/.391 with 55 RBIs in 196 games. St. Louis added more competition for Muñoz on the roster this spring, with Tommy Edman -- who had a breakthrough season last year -- and left-handed-hitting Brad Miller, who signed a one-year deal at the start of camp. Edmundo Sosa has also positioned himself as a backup shortstop and third baseman after impressing in winter ball and early in spring. He hit his second homer of the spring in Saturday's 5-1 win over the Astros.

“It’s very odd,” Mozeliak said. “But I knew there was frustration brewing, and last year, I knew there were some situations where he really wasn’t happy with how he was being used. … I try to sort of look at how this was going to end. I didn’t see a happy ending no matter how hard I tried.”