The Texas Rangers will be without one of their top relievers to start the season after hard-throwing Jonathan Hernandez was shut down from pitching for at least four weeks because of a ligament sprain in his right elbow.

Rangers general manager Chris Young said Tuesday that an MRI revealed a low-grade ulnar collateral ligament sprain after the right-hander felt something when throwing his last batting practice session.

Hernandez had a breakout season last year, when he was 5-1 with a 2.90 ERA in 27 appearances in the pandemic-shortened 60-game season. He had 31 strikeouts and eight walks in 31 innings, relying heavily on a sinker that averaged nearly 98 mph.

"The good news on him is that this (injury) is one that normally recovers and responds well with some rest," Young said from the team's spring training camp in Surprise, Arizona.

Young also said that outfielder/designated hitter Willie Calhoun is dealing with some mild groin tightness after playing Monday. The team planned to be cautious with Calhoun for a few days but didn't initially plan an MRI. That game came exactly one year after Calhoun was hit in the face by a fastball that broke his jaw during a spring training game.

Young said the Rangers would re-evaluate Hernandez after four weeks, and determine then if the 24-year-old's ulnar collateral ligament has healed enough to start a throwing program. He hadn't yet pitched in a spring training game and will need significant time to build back up once he can throw again.

"Jonathan is obviously one we were counting on," said Young, who expects the reliever to be out at least a couple of months. "This one hurts a little bit. But there's still a chance he pitches this year."

While Hernandez didn't have any save opportunities last season, he pitched in some high-leverage situations. The Rangers were expected to use him in similar role this year, with maybe some opportunities as the closer.

Jose Leclerc is coming back from a shoulder injury the closer sustained a week into last season, when pitched in only two games.

Left-handed Joely Rodriguez, who had a 2.13 ERA and struck out 17 in his 12 2/3 innings last season, is still behind in spring training because of a sprained ankle before getting to camp. He is expected to throw his first bullpen session Friday.

"Joely is behind, but he's made great progress," Young said. "We're encouraged by the progress he's made."

Fellow lefty reliever Brett Martin was scratched from his last scheduled appearance over the weekend because of lower back stiffness. Right-hander Joe Palumbo is also having back issues, but Young said both pitchers are expected to resume pitching next week.

Young said catcher Sam Huff, a top prospect who made his big league debut last season, is doing light baseball activity and light running while recovering from a strained left hamstring. Huff will get another MRI next week.