St. Louis Cardinals closer Carlos Martinez spent the night in the hospital after experiencing respiratory issues while warming up in the bullpen during Saturday's game, manager Mike Shildt told reporters, including Derrick Goold of the St. Louis Post-Dispatch.

Shildt added the team is "concerned for (Martinez's) health." Martinez was not at the ballpark for Sunday's series finale against the Milwaukee Brewers but had been discharged from the hospital, noted Goold.

Martinez fell ill while the team was visiting the Colorado Rockies in Denver but wasn't sure if allergies were the cause, Shildt explained, according to Goold. The right-hander shut himself down after having trouble breathing while warming up to enter Saturday's contest, which would have been his first appearance since his only game in Colorado.

The 27-year-old is in his first season as the Cardinals' primary closer after acting as a starter for the majority of his career. He's notched 19 saves and owns a 3.02 ERA and 2.88 FIP over 41 2/3 innings for the first-place club.

St. Louis entered the ninth inning of Sunday's game against the Brewers with a 4-3 lead, but Ryan Braun erased the deficit in the top of the ninth with a go-ahead grand slam off of Junior Fernandez, who blew the save.

Los Angeles Dodgers closer Kenley Jansen experienced similar issues while in Denver earlier this season. His ailment was eventually attributed to his irregular heartbeat due to the high altitude. Jansen underwent a second heart ablation procedure to correct the abnormal rhythm last offseason.