Stewart will not return to the Pirates after the club elected to decline its $1.5 million option for the 2018 season, Adam Berry of MLB.com reports.
Stewart played in 51 games for Pittsburgh in 2017, but he hit just .183/.241/.221 with no home runs and four RBI. He will look to latch on with another organization this winter, although it's unlikely that he will make much of a fantasy impact.