Mathews had previously signed a one-year non-guaranteed contract with the Celtics as the team entered training camp, while both Pinson and Clemons were signed as part of the Celtics training camp roster.
Guard and wing positions are an area of strength for the Celtics following their off-season acquisitions of Dennis Schroder and Josh Richardson, meaning Mathews and Pinson both had uphill battles to make the final roster.
The Celtics, who had the maximum 20 players heading into training camp, have been trimming down their roster over the last few days and had recently waived Ryan Arcidiacono and Juwan Morgan.
Since signing with the Celtics at the end of last season, Jabari Parker has been in impressive form and has continued to stake his claim for the team's final roster spot throughout the preseason. His non-guaranteed deal becomes guaranteed on October 20th when the Celtics open the season in New York. Bruno Fernando is on the final year of his rookie contract after being traded to Boston in the deal that sent Tristan Thompson to Sacramento.
Interestingly, the Celtics haven't extended a two-way contract to any of their waived players. Teams are permitted two players on two-way contracts each year, and currently, the second spot is unfilled with only three days to go before the start of the season.
Of the six players to have been cut by the Celtics, only Mathews will hit free agency. The remaining five players will report to the Maine Celtics for the start of the G-League season joining Quade Green, Jaysean Paige, Wayne Blackshear, Deng Adel, and John Bohannon, but will remain free agents should another NBA team show interest in their services.