Thompson was promoted from Triple-A Lehigh Valley on Thursday.
Thompson will take the place of Zac Curtis on the active roster as the Phillies look to replenish their bullpen ahead of Thursday's series finale against San Francisco. Over three long-relief appearances with the big-league club this season, Thompson has logged a 7.27 ERA and 1.62 WHIP with a 9:4 K:BB in 8.2 innings.