Both players have until 5 p.m. EST to accept. The Pirates would receive a compensatory draft pick if a player given the offer doesn't accept and then signs with another major league team before June 8.
Martin and Liriano have been vital parts of Pittsburgh's revival. The Pirates are coming off back-to-back playoff appearances following a record streak of 20 consecutive losing seasons.
The 31-year-old Martin hit .290 with 11 home runs and 67 RBIs in 111 games in 2014 and deftly handled a pitching staff that kept Pittsburgh in the NL Central title race until the final day of the regular season. The left-handed Liriano is 23-10 with a 3.20 ERA in two seasons with the Pirates.