CHICAGO -- The Pirates will begin the final month of the regular season without their ace.
Gerrit Cole was placed on the 15-day disabled list Monday due to posterior inflammation in his right elbow, the club announced. The assignment was made retroactive to Thursday, so Cole is eligible to return on Sept. 9.
Cole had been scheduled to start the Pirates' series opener against the Cubs on Monday night at Wrigley Field. Instead, he flew to Los Angeles for a second opinion on his sore throwing elbow. Shortly before Monday's game, Pittsburgh put Cole on the shelf and recalled left-hander Steven Brault to take his place.
Cole informed the club after his last start that he "had a little bit of discomfort on the outside of his elbow," general manager Neal Huntington told reporters over the weekend. Beyond that, the severity of the injury and Cole's timetable to return are unclear.
In five starts following his first career complete game on July 27, Cole went 1-3 with a 6.08 ERA, allowing 41 hits with only 22 strikeouts in 26 2/3 innings.
After allowing five runs on seven hits in five innings in a loss to the Astros on Wednesday at PNC Park, Cole chalked up his mistakes to poor execution and an inconsistent delivery, but he couldn't explain the cause of either. An injured elbow might help make sense of his slump.
Last season, Cole went 19-8 with a 2.60 ERA in 208 innings over 32 starts, finishing fourth in National League Cy Young Award voting. He avoided the disabled list entirely and credited his routine for his consistent success on the mound.
Cole dealt with two injuries -- shoulder fatigue and a back strain -- in 2014. He missed time in Spring Training due to inflammation in his ribs, an injury sustained in the offseason. In June, he left a start early and missed more than a month due to a strained right triceps.
With Cole out, the Pirates' Opening Day rotation has been completely overhauled. Gone are Francisco Liriano and Jonathon Niese (traded) as well as Jeff Locke and Juan Nicasio (in the bullpen). In came veterans Ivan Nova (trade) and Ryan Vogelsong (bullpen, disabled list) alongside rookies Jameson Taillon, Chad Kuhl and Brault, Monday's starter.
That group has actually pitched well lately despite Cole's extended skid. Pittsburgh's rotation ranks third in the NL with a 3.92 ERA since the All-Star break.
If the Pirates need further rotation help in Cole's absence, they could turn to Triple-A, where their options include top prospectTyler Glasnow, prospect Trevor Williams and right-hander Drew Hutchison, acquired in the Liriano trade.