The left-hander has been sidelined all season while recovering from a broken right arm. He made five minor league rehab starts -- three for Triple-A Indianapolis -- and struck out 33 with four walks in 21 2-3 innings. He was 2-1 with a 4.15 ERA.
Pittsburgh planned to clear a roster spot after Friday night's game or early Saturday. Pirates manager Clint Hurdle said the 29-year-old Liriano won't be on a strict pitch count after throwing 98 on Sunday in his third outing for Indianapolis.
"We're looking forward to getting him on a mound and see what the major league hitters tell us, him getting back in this environment, and see where it goes," Hurdle said.
Liriano and the Pirates agreed on a $12.75 million, two-year contract in December. But on Christmas, the day before he was supposed to fly to Pittsburgh and sign the deal, he broke his arm at home in the Dominican Republic. Liriano said he was injured when he slapped a door in his house.
The club revised its offer to Liriano and also signed Sanchez and Jeff Karstens to compete for jobs in the starting rotation.
A restructured contract was completed in February that guaranteed Liriano $1 million this year. But he was given the opportunity to earn $13.75 million plus award bonuses over two seasons in an incentive-laden deal.
He was an All-Star for the Twins in 2006, when he finished third in AL Rookie of the Year voting, but hasn't been quite the same since undergoing Tommy John surgery on his pitching elbow in November 2006. Liriano won 14 games and the AL comeback player of the year award in 2010 before throwing a no-hitter for Minnesota in May 2011, but he's been hampered by control problems.
"All the information we were able to gather, we felt this was a very good opportunity for him and for us," Hurdle said. "We believe he's in a very good point in time in his career to have a big bounce-back."