Thompson signed a minor-league contract Tuesday with the Phillies, Matt Gelb of The Athletic reports.
Thompson was cut loose from the Red Sox organization in May after struggling to a 5.40 ERA, 2.00 WHIP and 6:5 K:BB through 10 innings of relief this season at Triple-A Worcester. The 28-year-old right-hander will join up with the Phillies' Double-A affiliate in Reading.