Jonathan Hernandez, a promising reliever with the Texas Rangers, will miss the entire season after undergoing Tommy John surgery on Monday, according to Evan Grant of the Dallas Morning News. Hernandez had opened the season on the injured list because of what was described as a ulnar collateral ligament sprain. (The UCL is the same ligament replaced during the so-called Tommy John surgery process.)

Hernandez, 24, authored an impressive season last year, posting a 2.90 ERA (162 ERA+) and 3.88 strikeout-to-walk ratio in 27 appearances in what was his first full season as a reliever. He managed those numbers while accumulating the fourth-highest leverage index on the Rangers among pitchers with at least a handful of regular-season outings, behind Jose Leclerc, Rafael Montero, and Jesse Chavez

Coincidentally, Leclerc is also out for the season after undergoing Tommy John surgery. Given that Montero (traded) and Chavez (free agency) are elsewhere, it stands to reason that Hernandez would have been in line for additional high-leverage work this season -- and, perhaps, even standing in as Leclerc's replacement for the year.

Instead, the Rangers have had to turn over the ninth to veteran Ian Kennedy. Kennedy, who posted a 9.00 ERA in 15 appearances with the Kansas City Royals last season, has thus far converted both of his save opportunities. In four total appearances, he's managed a 4.50 ERA and has struck out six batters without issuing a walk.

The Rangers also announced that right-hander Matt Bush will miss several months of his own because of a strained flexor tendon.

The Rangers entered Monday's series opener against the Tampa Bay Rays with a 3-6 record on the year. Texas, having finished with the second-worst record in Major League Baseball last season, is not expected to compete for a playoff spot this year.