Liriano will start Saturday against the Dodgers in Los Angeles, then the Pirates will push back his next scheduled start -- which would have been Wednesday in Colorado -- until Sept. 26 at Wrigley Field.
"We wanted to give him a little bit of a break, push his start back a few days. He understood completely," Pittsburgh manager Clint Hurdle said. "I think he feels very good about it and is ready to take advantage of it, then get back on the mound."
Following Burnett and J.A. Happ will be right-hander Charlie Morton, who will start the Pirates' third game against the Rockies in Liriano's place. Left-hander Jeff Locke is scheduled to start the series finale at Coors Field.
After that, the Bucs will send Cole, Liriano and Burnett to the mound in another potentially critical three-game series against the Cubs from Sept. 25-27 at Wrigley Field.
The Pirates swept the past four series in which they started those three pitchers, and they won the final three games of a four-game set against the Cardinals behind Cole, Burnett and Liriano.
Hurdle said the Pirates' rotation for their final two series of the year -- against the Cardinals and Reds at PNC Park -- is currently written "in pencil." Cole is likely to start the final game of the Cards series, setting him up to start the Bucs' first postseason game.
Around the horn
• The Pirates' season-long struggles to control the running game persisted Wednesday night, as the Cubs stole five bases en route to a 3-2 win.
Hurdle said the Bucs continue to emphasize the importance of holding and throwing out runners, but there were a few cases Wednesday where they simply chose not to make a throw down to second base.
"A couple times, we wanted to maintain position defensively on the diamond, not worry about the throw and take care of the hitter," Hurdle said. "I think we're still trying to find ways to improve."
• One aspect of the Pirates' running game that has taken a step forward: Gregory Polanco's sliding. The 24-year-old outfielder has been caught stealing 10 times this season -- often the result of poor slides -- but he looked smooth sliding into second base Wednesday night, picking up his 25th steal of the season.
"The fact that we're not talking about it anymore, I think, kind of puts an exclamation point on that," Hurdle said. "It's improved a lot."