The Giants released Matzek (elbow) on Friday, Alex Pavlovic of NBC Sports Bay Area reports.
No team was interested in claiming Matzek after the Giants placed him on waivers Wednesday, so the 33-year-old lefty will now get to choose where he plays next -- likely on a minor-league deal. He has been out since May due to elbow inflammation but is expected to be ready to pitch again at some point in September.