JUNE 12: Cahill has been optioned to the Diamondbacks’ Single-A Advanced affiliate, the club announced on Twitter. He will take the ball as the starter for Visalia tonight, tweets Nick Piecoro of the Arizona Republic, which confirms both that he has accepted the assignment and that he will look to stretch out again as a starter.

JUNE 10: The club has secured optional waivers on Cahill, tweets Jack Magruder of FOX Sports Arizona, meaning that he can be sent to the minors if he consents to the assignment.

JUNE 9, 7:48pm: Cahill has indicated that he would be amenable to taking a minor league assignment, tweets MLB.com’s Steve Gilbert.

5:58pm: The Diamondbacks announced today that they have designated right-hander Trevor Cahill for assignment as part of a series of transactions (Twitter links). The club also reinstated J.J. Putz from the 15-day disabled list, recalled Will Harris from Triple-A Reno, and placed Eric Chavez on the 15-day DL.

Now 26, Cahill came to Arizona from the Athletics (along with Craig Breslow) back in December of 2011. The Diamondbacks gave up a significant haul to acquire his rights, parting with Jarrod Parker, Collin Cowgill, and Ryan Cook. While Cowgill has moved on from Oakland, both Parker and Cook are key parts of the club’s staff (though the former is out for the year for Tommy John surgery and the latter has been limited with his own arm troubles).

Less than a year before he was dealt, Cahill had signed a five-year, $30.5MM pact with Oakland. That contract, no doubt, was part of his appeal, especially as he owned a 3.91 ERA through 583 career innings at the point of the trade. Though he was coming off of a less impressive 2011 campaign, the then-23-year-old had tossed 196 2/3 innings of sub-3.00 ERA ball in 2010.

Now, of course, most if not all of the remainder of that contract is likely to stay on Arizona’s books — and it no longer looks like a bargain. While Cahill combined for 346 2/3 innings of 3.87 ERA ball in his first two seasons with his new club, he missed time last year with a hip injury and has struggled to a 5.66 ERA through 41 1/3 frames in 2014. Though he is striking out batters at a 9.6 K/9 rate that is far and away the best in his career, he is also surrendering a career-low 5.4 BB/9 while dropping below a 50% groundball rate for the first time since his rookie year.

On the other hand, since shifting to the pen, Cahill has worked to a 3.04 ERA while holding the opposition to a .681 OPS. And on the whole, advanced metrics see Cahill as being much the same pitcher now as he has always been. For instance, since his first year in the bigs, his SIERA has never been above 4.11 or below 3.84 (and stands at 3.96 for 2014).

The contract, which includes successive club options for 2016-17, guarantees Cahill the rest of his $7.7MM salary this year as well as $12.3MM for 2015 and a buyout. The question becomes whether not only those obligations, but also Cahill himself, will stay in Arizona. GM Kevin Towers says that the “hope is to retain him,” as the team “still think[s] there is value there,” reports Jesse Sanchez of MLB.com (via Twitter).

Though he has options available, as a veteran with over five years of service time to his name, Cahill would need to agree to any assignment from the D’backs — and would not sacrifice future salary if he declines. Towers implied that he has agreed to do just that, says Nick Piecoro of the Arizona Republic (links to Twitter): “There’s a game plan in place for what we’re ultimately going to do, but as of right now he’s just designated.” Presumably, the club would allow Cahill to try to work out his issues while stretching back out as a starter.

Jeff Todd contributed to this post.