Diamondbacks' Shelby Miller has torn UCL and is facing Tommy John surgery

Miller is weighing his options, but Tommy John surgery seems likely

At 14-9, the Arizona Diamondbacks are off to a far better than expected start to the season. Alas, the D-Backs received some bad news on Thursday.

Right-handed starter Shelby Miller, who left his most recent start with what was described as a strained forearm, has officially been diagnosed with a torn UCL and a flexor strain:

#Dbacks Shelby Miller has tear in UCL. Evaluating his options. Also has flexor strain.

— Steve Gilbert (@SteveGilbertMLB) April 27, 2017

.@Aces #Dbacks select LHP T.J. McFarland from the Triple-A Reno @Aces and transfer RHP Shelby Miller to the 60-day DL.

— Arizona Diamondbacks (@Dbacks) April 27, 2017

Here's Miller discussing the injury:

"Terrible news; it sucks," #Dbacks Miller addresses injury to right elbow pic.twitter.com/TcIJbEKT4M

— Craig Grialou (@CraigAZSports) April 27, 2017

Although Miller hadn't lived up to the hype stemming from his impressive 2015 (or the subsequent trade to Arizona), he had done a better job in 2017 than in '16. Sure, his strikeout-to-walk ratio remained subpar, but he'd allowed just a single home run over his first four starts -- a marked improvement from last season, when he averaged a career-worst 1.2 home runs per nine.

Now, Miller seems likely to undergo Tommy John surgery, costing him the rest of the year as well as at least some of 2018. 

The D-Backs started Zack Godley in Miller's place on Wednesday, but afterward he was optioned back to the minors. It's unclear who will join the rotation heading forward, but all eyes will remain on Archie Bradley -- whose transition to the bullpen has gone very well -- until Arizona decides on its replacement. In theory, the D-Backs could turn to a youngster like Braden Shipley or Anthony Banda, though neither has pitched well thus far in Triple-A.

Whatever the case, it's not great news for one of baseball's most surprising early season successes.