Bassey became a free agent Saturday after his second 10-day contract with the Celtics expired, Keith Smith of Spotrac.com reports.
The fifth-year center was a depth option for Boston over the course of his pair of 10-day deals, making five appearances while averaging just 2.8 points and 1.2 rebounds in 3.4 minutes. Boston will have the ability to retain Bassey on a rest-of-season deal, though it's unclear if the Celtics intend to do so.