Hamels asked for a patch in memory of Phillies chairman David Montgomery who passed away earlier this month.
The team is wearing the emblem with the initials 'D-P-M' to honor Montgomery.
Along with his role in the Phillies front office, Montgomery gave much of his time and effort in volunteer positions at PHL Sports, a division of the Philadelphia Convention & Visitors Bureau; the Greater Philadelphia Chamber of Commerce; Need in Deed, a non-profit working with children in Philadelphia public schools; the Children's Scholarship Fund; and the Walnut Street Theatre.
Hamels credits Montgomery for sparking his own charitable spirit during his time in Philadelphia.
Hamels earned a no decision in his first game against his former team Wednesday night. The Cubs won 8-4.