Houston Astros closer Josh Hader's availability for Opening Day is in doubt because the left-hander is dealing with biceps soreness, manager Joe Espada told reporters Wednesday.

Hader, a six-time All-Star, resumed his throwing program at the team's first workout with pitchers and catchers Wednesday. Espada revealed Hader had been shut down from throwing for more than a week earlier this winter after imaging on his left arm showed biceps inflammation.

Neither Espada nor Astros general manager Dana Brown could say if the injury would keep Hader off the Opening Day roster.

"I don't know really the timeline on it," Brown said Wednesday. "The good thing is he was ramping it up and was on his fourth (bullpen session). The first three were seamless. The good thing is he feels good right now, he's been feeling good for a few days and he's going to throw today."

The injury is not believes to be related to the left shoulder capsule strain that caused Hader to miss Houston's final 46 games last season, the first time he had been on the IL in nine seasons for anything but an illness. Hader told reporters at a charity event in December he felt "back to normal" from the shoulder capsule injury.

Hader was 6-2 with a 2.05 ERA over 48 appearances with the Astros last season and was 28-for-29 in save opportunities.

The 31-year-old has 227 saves over nine big-league seasons with the Milwaukee Brewers (2017-22), San Diego Padres (2022-23) and Astros (2024-25). He is 34-31 with a 2.64 ERA in 468 career relief appearances.