March is typically a tough month for pitcher injuries, and the Oakland Athletics were dealt a blow this week. Right-hander Jharel Cotton suffered an elbow injury and will soon undergo Tommy John surgery. He'll miss the 2018 season.

Cotton, who came over from the Los Angeles Dodgers in the Rich Hill/Josh Reddick trade two years ago, threw 129 innings with a 5.58 ERA (76 ERA+) last season. Despite that performance, the 26-year-old was considered a 2018 breakout candidate by some because he has a dynamite changeup and gained valuable MLB experience last year.

MLB: Oakland Athletics at Houston Astros
Jharel Cotton will miss 2018 with Tommy John surgery. USATSI

At the moment, the A's rotation depth chart looks something like this:

  1. Kendall Graveman
  2. Sean Manaea
  3. Jharel Cotton (will miss 2018)
  4. Daniel Mengden
  5. Paul Blackburn
  6. Andrew Triggs
  7. Daniel Gossett

Graveman is rock solid and Manaea has considerable upside, otherwise that doesn't look to be the most reliable rotation in the world. Not surprisingly, president of baseball operations Billy Beane indicated on Saturday that the A's will look to the free agent market for rotation help in the wake of the Cotton injury.

Alex Cobb is, far and away, the best available pitcher on the free agent market right now. Other unsigned free agents include R.A. Dickey, Ubaldo Jimenez, Matt Garza, and former Athletics hurlers Brett Anderson and Trevor Cahill. If the A's don't want to spend big for Cobb -- they'd have to surrender a draft pick to sign him -- a reunion with Cahill may be in the cards. He pitched well for the San Diego Padres early last year before being traded to the Kansas City Royals.

The A's open the 2018 regular season at home against the Los Angeles Angels on Thursday, March 29. Manager Bob Melvin is expected to tab Graveman for his second consecutive Opening Day start.