The Cubs acquired Robertson from the Phillies on Tuesday in exchange for right-hander Ben Brown, Jeff Passan of ESPN.com reports.
Robertson will rejoin the team he signed a two-year deal with back in 2019. He's had a couple rocky outings since the start of July -- including his last one -- but he saved 14 games for the Cubs and owns a 2.23 ERA and 1.04 WHIP on the season, so he's sure to provide a boost to the back end of the Phillies' bullpen. Seranthony Dominguez and Brad Hand are likely to move into setup roles to clear the way for Robertson to serve as the Phillies' primary option in save situations.