Matthews was held scoreless in two minutes during Sunday's G League loss to Wisconsin.
Matthews will play for the 76ers' Summer League team, Keith Pompey of The Philadelphia Inquirer reports.
Matthews was waived by the Cavaliers on Friday, Chris Fedor of The Cleveland Plain Dealer reports.
Matthews (knee) is probable for Friday's preseason game against the Knicks, Chris Fedor of The Cleveland Plain Dealer reports.
Matthews did not play in Wednesday's 100-93 preseason loss to the Knicks due to right knee soreness.
Matthews is out for Saturday's preseason opener against the Pacers due to right knee soreness.
Matthews (knee) said Sunday that he agreed to a contract with the Cavaliers, Brendan Quinn of The Athletic reports.