Pirates prospect Nick Kingham underwent Tommy John Surgery

Pirates pitching prospect Nick Kingham underwent Tommy John surgery yesterday, the team announced. The rehab will force Kingham to miss the rest of 2015, along with a large part of the 2016 season.

It's a disappointing setback for Kingham, who was rated by Baseball America and MLB.com as the team's sixth-best prospect. In 119 innings with Triple-A Indianapolis, Kingham was 6-6 with a 3.77 ERA. He was was looking so promising in 2015, that the Pirates were discussing whether or not he could make his debut at some point this season.

While not the top pitching prospect in system, Kingham was the most likely arm to help Pirates in 2015

— Travis Sawchik (@Sawchik_Trib) May 28, 2015

Kingham was originally drafted back in 2010 and rose through the minor league ranks steadily, reaching Triple-A last season. He's been viewed as a potential number four starter for the Pirates going forward.

What does this mean for the Pirates?

For the moment, not much. The Pirates rotation as it is constructed now has the second best ERA in the league. It just so happens that the team in front of them is their division rival, the St. Louis Cardinals. Gerrit Cole has been the ace that those in the Pirates front office drafted, while A.J. Burnett and Francisco Liriano are stabilizing the rotation with their veteran presence. At the back end both Jeff Locke and Vance Worley have proven to be reliable.

The Pirates seemingly have a lot of pitching depth, as Charlie Morton just returned from injury and in Triple-A they have Casey Sadler, Chris Volstad, Clayton Richard, Adrian Sampson and Wilfredo Boscan.

Where Kingham really matters is when Burnett likely retires after this season. Kingham was viewed as the guy that could step in and take his spot with a relatively smooth transition, but that's not longer an option. This could mean the Pirates may try to bring Burnett back for one more year, or explore a different solution in the open market.