Cust, 32, was released by the Mariners earlier this summer after struggling with 69 games primarily as the club's designated hitter. The Phillies have long been searching for a quality pinch-hitter off the bench, they've been using Ross Gload and John Mayberry Jr. in this role for most the season, and they had nearly filled it last month with a trade for Jason Giambi. The younger Cust hasn't hit as well as Giambi lately, but he does offer similar power/patience potential.
Cust hasn't hit much this season, but from 2007 through 2010, Cust hit a combined .247/.381/.457 with an average of 24 homers and 94 walks each season. That's good for a 125 OPS+; pretty much every team can use that kind of bat in some role, although obviously we haven't seen that Jack Cust yet this year.