Frieri pitched an inning Monday night, allowing no runs on a hit and a walk. He is 1-0 with a 4.63 ERA and two saves in 22 games this season.
"Ernie did a nice job for us," Cash said. "We kind of felt going forward that we were maybe better suited for somebody who could give us a little more length. Not to say that Ernie can't, but he's been a one-inning pitcher for most of his career.
"Tried to buy some time to work some kinks out for him. We hope he has the opportunity to go somewhere else. If he doesn't, we would love to have him to work some more stuff out in Durham."
Cash was asked how tough it was for him as a manager to deliver the news to the veteran reliever.
"You know what, he was great," Cash said. "Could not have complimented the organization or teammates more. This will come as a little bit of a blow to the guys because he is so liked in the clubhouse."
This will be Mahtook's second stint with the team this season. He has one hit in four at-bats, with that one hit being a two-run homer in Toronto.
Bill Chastain is a reporter for MLB.com This story was not subject to the approval of Major League Baseball or its clubs.