Diamondbacks’ Robbie Ray has strained oblique

Diamondbacks left-hander Robbie Ray has been diagnosed with a strained right oblique, per a club announcement Sunday afternoon. Arizona hasn’t released specifics on the severity of the injury, but oblique strains generally cost pitchers three or four weeks at the minimum and can often keep them out for months at a time.

The loss of Ray, 26, will be a huge one for the Diamondbacks, especially since they’re already without a key front-of-the-rotation arm in Taijuan Walker, who underwent Tommy John surgery earlier this month, and haven’t had Shelby Miller, who also had Tommy John, since April of last year.

Through six starts this season, Ray has a 4.88 ERA and 1.52 WHIP with 45 strikeouts and 17 walks in 27.2 innings. He’s failed to make it to the end of the fifth inning in four of those starts — including Sunday’s against the Nationals, during which he was pulled in the second inning due to the injury — but in both of the starts during which he’s lasted six innings, he’s allowed two or fewer runs. He finished seventh in NL Cy Young voting last year after a breakout season during which he posted a 2.89 ERA and 1.15 WHIP over 28 starts.

Based on minor-league performance to this point, no one in the rotation at Triple-A Reno is particularly deserving of a call-up. Big-league veterans Troy Scribner, Kris Medlen, Jake Buchanan, and Albert Suarez all have ERAs above 5.00 this season. Taylor Clarke, their No. 7 prospect according to MLB Pipeline, is in the Aces’ rotation but has posted an abysmal 7.43 ERA and 1.78 WHIP over five starts this year. Former first-round pick Braden Shipley, who is probably most likely to get the first crack at filling Ray’s spot since he’s already on the 40-man roster, has a 6.26 ERA and 1.54 WHIP through five starts. It’s worth noting that the D-Backs could move Walker, who is still on the 10-day DL but obviously will miss the rest of the season, to the 60-day disabled list if they want to add Buchanan, Clarke, Medlen, or Suarez to the 40-man roster.

Randall Delgado, who is primarily a reliever at this point but has served as a fill-in starter for the D-Backs in the past, is currently on a rehab stint at High-A Visalia and could be an option to fill in for Ray whenever he returns from the oblique strain that has plagued him since the beginning of spring training.