Chase Whitley to have season-ending Tommy John surgery

The New York Yankees rotation depth is about to be tested. Pitcher Chase Whitley will have season-ending Tommy John surgery Tuesday, according to Ken Rosenthal of FoxSports.com.

The news doesn't come as a huge surprise. Whitley left his last start with elbow discomfort, and an MRI revealed a partial tear of his UCL. Whitley received a second opinion, but ultimately decided to have surgery over attempting to rehab the injury.

Once Whitley has the surgery, he'll join ace Masahiro Tanaka on the disabled list. Tanaka is also dealing with a tear in his UCL, but opted for the rehab route. He's currently working his way back from a forearm issue, but was able to throw a bullpen session Monday.

Though it appears Tanaka is nearing his return, the Whitley injury highlights the lack of pitching depth in New York. The rotation entered the season with major question marks, and many of those still remain despite the team's hot start.

Tanaka lasted just four starts before going back on the disabled list, Nathan Eovaldi looks pedestrian after a promising spring and CC Sabathia continues to battle with diminished stuff. That's not to say Sabathia or Eovaldi have been bad, but neither looks poised to blossom into an ace any time soon.

Michael Pineda has done that, but questions remain about his ability to hold up over a full season. While Pineda has been exceptional, he only threw 76 1/3 innings last year. It's unclear whether the team will limit his innings if he's able to stay healthy.

On top of all those issues, the team will now be without Whitley for the remainder of the season. Whitley wasn't anything special, but he was fine as a back end starter. His strikeout rate and walk rate were both slightly above average, and his 4.19 ERA was almost exactly average among starters this season. The Yankees aren't losing an ace here, but Whitley's absence gives more responsibility to lesser players.

For now, Chris Capuano is expected to replace Whitley in the rotation. After missing time early in the season with a quad injury, he allowed four runs over three innings in his debut. The move also ensures Adam Warren will receive more time in the rotation moving forward. Both players lack upside, and neither have compiled a lot of innings in recent seasons.

Ivan Nova is currently working his way back from Tommy John surgery, and is expected to rejoin the club in June or July. Nova has far more upside than Capuano or Warren, but, again, his innings will likely be limited.

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That's the big theme here. There's not one pitcher on the team who is a lock to exceed 200 innings. Sure, Sabathia has done it before, but he's coming off knee surgery. Most of the players the team was set to rely on at the back end, including Whitley, also didn't have that experience coming into the season.

All of those issues remain, and now Whitley won't be around to take pressure off some of those questionable starters. While Whitley may not have been able to give the Yankees 200+ plus innings, he was at least going to give them an average performance. You can't say that about his replacements.

The loss of Whitley alone won't be a major deal for New York. The domino effect it will have on the club's already thin pitching staff could be devastating.

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Chris Cwik is a writer for Big League Stew on Yahoo Sports. Have a tip? Email him at christophercwik@yahoo.com or follow him on Twitter! Follow @Chris_Cwik