"It's tough," Cotton said. "I'm missing the 2018 season with my boys, so it's kind of hard to take. I'm trying to take it as best I can and get ready for the long process, the long road ahead, come back strong next season."
An already wobbly A's rotation, which features minimal experience beyond Kendall Graveman and Sean Manaea, can hardly afford such a development. Daniel Mengden, Paul Blackburn and Andrew Triggs are strongly favored to fill out the Opening Day rotation, with Daniel Gossett and prospect A.J. Puk also in the mix.
A new candidate is on the way, however. Lacking extra bodies, the A's quickly went to work to remedy this Saturday, agreeing to terms on a one-year deal with former Oakland All-Star Trevor Cahill, per a club source. It's unlikely Cahill will be ready to start when the regular season opens, but he could potentially work in long relief and be a starting option down the road.
Hours prior, A's executive vice president of baseball operations Billy Beane addressed the media, saying, "We didn't have very much depth coming in, and we have less now. So we have no choice but to go out there and look.
"It's not exactly fertile ground for finding a starting pitcher, and certainly there are limitations as it relates to cost."
Even with Cahill aboard, the A's likely aren't done looking, since Beane suggested he would ideally reel in multiple arms.
Additional depth would allow the A's to keep Puk, who has never pitched above the Double-A level, in the Minors for several weeks. This seems to be the prudent thing to do, rather than promoting him at season's start.
"If he is [promoted], it's only because we don't have a lot of options," Beane said. "The preferred route is not to jump a kid after half a year in Double-A. That's the preferred route, it's not always the one you have the option of taking."
Cotton, 26, was 9-10 with a 5.58 ERA in 24 starts during his 2017 rookie campaign, and "it was looking like he would be in our rotation for sure," manager Bob Melvin said, "so someone else is going to have to step up as far as that goes."
This will have ramifications on the bullpen; Melvin is seeking a true length man to round out what he believes will be an eight-man assembly, and one of the ideal candidates, Triggs, is needed in the rotation. Raul Alcantara, who is out of options, is among those who will be under consideration. Frankie Montas, who profiles similarly, is on the mend from a shoulder injury and likely won't be ready for the season.
"Once we decide the five [starters], then we'll take a look at who our length could be," Melvin said, "but we feel like we have several options."
Cotton was enjoying an impressive spring before being victimized by a torn ulnar collateral ligament in his elbow, pitching to a 3.75 ERA in four Cactus League outings and flashing the form that the A's have been eager to see from him on a consistent basis.
"It's unfortunate, just for him having to go through what a lot of guys have to go through," Melvin said. "We felt like he was on the cusp of really coming into his own, and [that is] just going to be delayed a year unfortunately.
Jane Lee has covered the A's for MLB.com since 2010. Follow her on Twitter @JaneMLB.