According to The Denver Post reporter Mike Singer, sources revealed that the reason is Jason Terry signed Isaiah Thomas to a nugget development league affiliate. Terry is the manager of a nuggets development league affiliate and is good friends with Thomas Jr.
Sources revealed that Thomas Jr. had a chance to eventually be called up by the Nuggets from the development league. In the 2020-21 season, Thomas Jr. played in 3 games for the Pelicans, averaging 16 minutes per game, with 7.7 points, 1.3 rebounds and 1.7 assists.
Thomas Jr. played in 528 games during his NBA career, averaging 28.8 minutes per game, 18.1 points, 2.4 rebounds and 4.9 assists.