Stolmy Pimentel was activated from the disabled list, and the right-hander will take Liriano's roster spot. Manager Clint Hurdle said he was unsure of who would make Liriano's next scheduled start, which will come on Sunday in Miami.
Pimentel, who was sidelined since early May with inflammation in his right shoulder, is a candidate. He was used in a relief role before his injury and has never made a Major League start, but he made 148 starts in the Minors in 154 appearances. Hurdle mentioned reliever Casey Sadler as another option, adding that the team could dip to the Minors as well.
"Internally, [Sadler] is one of the names we're talking about," Hurdle said. "[Pimentel's] name, I imagine will be in. And we'll revisit with our Triple-A staff on guys that are there, as well, that could make that start."
If the Pirates do go in the Minor League direction, it will probably be a move for Vance Worley. The 26-year-old righty, who is 3-2 with a 4.30 ERA in seven starts for Triple-A Indianapolis, has 56 Major League starts to his name. His next start is slated for Friday.
Whoever the Pirates choose to start Sunday may be doing so for just one outing. Cole is on schedule to come off the DL next week, and the Pirates have a day off Monday.
Liriano, who is 1-6 with a 4.60 ERA in 14 starts and 72 1/3 innings this season, said he hasn't previously had an issue with his oblique, but this marks the sixth trip to the DL in the 30-year-old's nine-season career. Liriano's last DL stint was because of a fracture in his right forearm and delayed the start of his 2013 season.
With Cole going on the DL on Sunday with right shoulder fatigue and the Pirates designating left-hander Wandy Rodriguez for assignment three weeks ago, the team currently has just two of the five starters it began the season with.
Tom Singer is a reporter for MLB.com and writes an MLBlog Change for a Nickel. He can also be found on Twitter @Tom_Singer. Stephen Pianovich is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.