The Nationals recalled La Sorsa from Triple-A Rochester ahead of Wednesday's game against the Cardinals, Andrew Golden of The Washington Post reports.
He'll be joining the big-league bullpen as a replacement for Carl Edwards, who was placed on the 15-day injured list with right shoulder inflammation. La Sorsa made a pair of relief appearances in the majors with the Rays earlier this season, but he'll be joining the Nationals for the first time since Washington claimed him off waivers June 8.