Jim Salisbury of CSNPhilly.com notes that this move gives the team more options at catcher:
The move gives the Phils three catchers, but more importantly a full bench for Wednesday night’s game against the Atlanta Braves. The Phillies had played short on the bench for three games after Thome strained his lower back on Saturday night.
Kratz, the 31 year-old recalled to replace Thome on the roster, has very little experience in the Majors, with just 11 games and 42 plate appearances on his resume. In that short time, he has a .150 / .190 / .175 line, with one double and no home runs. He's hitting .294 in 54 plate appearances for Lehigh Valley.
Matt Gelb of the Philadelphia Inquirer notes that the Kratz recall makes sense because he was already on the 40-man and there were "a dearth of other options."