Liriano has spent the past two seasons with the Pirates. The deal was reported earlier Tuesday by CBS Sports.
The 31-year-old went 7-10 with a 3.38 ERA last season. In 2013, he posted a career best in victories, finishing with a 16-8 record and a 3.02 ERA after signing a one-year contract with a vesting option for 2014 with the Pirates that was delayed after Liriano injured his non-pitching arm over the holidays.
Pittsburgh has posted back-to-back winning seasons and has reached the playoffs each of the last two years following a 20-year postseason drought.