Matz (ankle) will embark on a rehab assignment Thursday, Marc Topkin of the Tampa Bay Times reports.
Matz is ready to take the last step in his recovery from a left ankle sprain that caused him to land on the 15-day injured list in late June. He may need just one or two outings in the minors before he's ready to return to the big club, though it's unclear whether his reinstatement from the IL will come before or after the All-Star break.