Cahill struggled as a starter at the beginning of the year and after showing some initial improvement when he was moved to the bullpen, his struggles continued. In 19 games (four starts) he was 1-6 with a 5.66 ERA.
The team has met with Cahill over the last several days to discuss some options.
The most likely appears to be the team would option him to the Minor Leagues -- maybe Class A Advanced Visalia -- where he could work out some of his issues as well as get stretched out to become a starter, a role that both parties think he's best suited for.
Because of his service time, Cahill has the right to decline an option and therefore become a free agent.
"We've talked to Trevor at length, we talked to his advisor," D-backs general manager Kevin Towers said. "There's a gameplan in place for what we're ultimately going to do, but as of right now he's just designated. Because of service time and where he's at, there's a lot of hurdles and hoops you've got to jump through. The reason I can't be totally upfront is there are a lot of things that can still happen in the next couple of days. I hate to put the cart in front of the horse right now."
Should Cahill decline to go to the Minor Leagues, he would become a free agent with the D-backs still on the hook for the nearly $18 million left on his contract. Cahill is still owed about $5.6 million the rest of this season and $12 million in 2015. The team holds options for 2016 and 2017 with a $300,000 buyout for the first option.
Cahill seemed to indicate that he would accept an option to the Minors without definitely saying that.
"The way I'm throwing right now I don't know necessarily what the outcome of that would be," Cahill said of electing free agency. "I just want to get back to being a starter and right now I'm not built up. I'm sure they've got a plan and I trust them and I feel like they'll do right by me. They haven't given me an indication that they wouldn't. So I'm just going to do whatever's best for the team. I like playing here. I want to stay here, but I want to get better and be the guy that I can be."
Steve Gilbert is a reporter for MLB.com. Read his blog, Inside the D-backs, and follow him on Twitter @SteveGilbertMLB. This story was not subject to the approval of Major League Baseball or its clubs.