Phillies place slugger Jim Thome on DL
Thome has not played since leaving Saturday night's game with tightness on the left side of his lower back. The move was made retroactive to Sunday.
The 41-year-old Thome is hitting .111 with no homers or RBI and 10 strikeouts in 18 at-bats.
Kratz, who hit .294 with three homers and nine RBI at Lehigh Valley, will fill Thome's primary role as a pinch-hitter. The 31-year-old Kratz hit a combined .150 in brief appearances with Pittsburgh in 2010 and the Phillies last season.