Martin Perez's season is likely over after an MRI revealed a UCL tear in his pitching elbow. (Jim Cowsert/AP)

The Texas Rangers' rotation, which has been beset by injuries all season, received its hardest blow yet on Wednesday with the news that Martin Perez may require Tommy John surgery and Matt Harrison may require career-threatening spinal-fusion surgery. The Rangers placed both pitchers on the 15-day disabled list on Tuesday, and both will pursue rehabilitation and further medical opinions before going under the knife, but the outlook for both — and for Texas' postseason hopes — is bleak.

Perez, a 23-year-old sophomore, was the only member of the Rangers' intended Opening Day rotation to make it to Opening Day, as injuries re-routed Harrison (back), Derek Holland (knee surgery), and Yu Darvish (neck) to the disabled list and Alexi Ogando to the bullpen. He opened the season gong 4-0 with a 1.42 ERA in his first five starts, the last two of which were three-hit shutouts, but in his three starts since, he had allowed 19 runs in 13 1/3 innings with at least as many runs allowed as innings in all three outings. He likely won't have a chance to improve on those numbers this year: The lefty has been diagnosed with a partial tear of the ulnar collateral ligament in his pitching elbow.

Perez's injury is an interesting exception to the recent spate of UCL injuries, as the Venezuelan-born Perez is not a product of an American high school. As covered in depth by SI's Tom Verducci, the prevailing theory regarding the increased incidence of Tommy John surgery — one put forth by no less an expert than Dr. James Andrews, the world's leading Tommy John surgeon — is that teenage pitchers are being overworked and are overthrowing in high school. However, if Perez does opt for the surgery, it would mean that three of the last five major leaguers to do so were signed out of Latin American countries, with Perez joining the Yankees' Ivan Nova and fellow Ranger Pedro Figueroa, both of whom are from the Dominican Republic.

Given Perez's youth and his new contract (a four-year deal with three club options in November), he should still have a bright future as a Texas Ranger, even if he does have the surgery, which would schedule his next major league pitch for no sooner than next May. Harrison, however, is facing a far more dire circumstance.

Harrison has been diagnosed with spondylolisthesis, a forward displacement of a vertebra which causes severe nerve irritation, in the lumbosacral joint (L5-S1) in his lower back. Far more severe than even a slipped disc (which is a tear in one of the cartilaginous joints in the back), spondylolisthesis means that Harrison's lower back is effectively dislocated. The recommended surgical solution is a spinal fusion, which could prove career-ending. Broncos quaterback Peyton Manning, Cubs outfielder Ryan Kalish, and retired Blue Jays reliever Pete Walker all came back successfully from spinal fusion surgery, but all three had the fusion in their neck. Harrison is facing surgery down near the base of his spine, a very different situation.

There's some slim hope that rest, rehab, and a high pain tolerance could allow Harrison to return to the majors without the surgery, but the prognosis is no more encouraging via that route and could make Harrison's life off the field far more difficult, as he could be dealing with constant pain. Harrison already had two surgeries on his lower back last year and also dealt with thoracic outlet syndrome in his right (non-pitching) shoulder during his rehabilitation, having previously suffered from the condition in his left shoulder in 2009. Harrison has now been limited to six starts over the 2013 and '14 seasons combined, only one of which, his debut this season, was a quality start, and will turn 29 in September. The odds against his successful return are long.

The Rangers' rotation woes don't end there. After a solid start to his season, converted reliever Robbie Ross has allowed 21 runs in 15 1/3 innings over his last three starts. Tanner Scheppers, the other reliever the Rangers converted to the rotation to start the season, posted a 9.82 ERA before landing on the disabled list with an inflamed elbow, having most recently thrown approximately 30 pitches in a bullpen session. Lewis returned in mid-April but has yet to complete six innings in any of his six starts. Holland isn't due back until July.

As far as replacements for Perez and Harrison, sophomore Nick Tepesch pitched well in Perez's place Wednesday night (5 1/3 IP, 2 H, 1 R, 3 BB, 8 K), and Joe Saunders is due back next week from an ankle injury suffered in his season debut. The Rangers have also recalled former Twins starter and 2012 Tommy John recipient Scott Baker and have rookie starter Nick Martinez, part of their makeshift Opening Day rotation, in their bullpen. So there are bodies there to take the place of the ones that have broken, but there's not much cause for optimism in the near-term.

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