Allen hit .270 with four doubles, a triple, two RBI and five stolen bases in 15 games with New York in 2021. The 28-year-old switch-hitter played each outfield position multiple times.
The Pirates have All-Star Bryan Reynolds in center field and Ben Gamel played solidly in left field but right field is wide open. The Pirates waived Gregory Polanco in late August and used a variety of players following his departure, including Yoshi Tsutsugo, who became a free agent on Thursday.
Allen is a career .241 hitter in the majors, with stops in Cleveland, San Diego and New York. He hit an impressive .326 in 73 games with Triple-A Scranton/Wilkes Barre last season.