Pittsburgh recalled Eisert from Triple-A Indianapolis on Monday.
After being optioned to Indianapolis last Wednesday, Eisert will rejoin the Pirates less than a week later with Mitch Keller (arm) going on the 60-day injured list in a corresponding move. Over 32 appearances in the majors this season between stops with the White Sox and Pirates, the left-handed reliever owns a 6.29 ERA, 1.40 WHIP and 40:12 K:BB across 34.1 innings.