Allen, who holds 47 games of NBA experience, most recently played in France. He had been on an NBA roster in each of the past three seasons (Boston in 2017/18, along with New York the next two years), but he failed to make a team this year.
Across his 15 games in France, Allen averaged 9.3 points, 2.6 assists and 18.3 minutes per contest. He also shot 55% from the floor and 39% from deep.
Allen was the No. 53 pick to Boston in 2017. He spent two years at Arizona before entering the draft, spending much of his professional career to date in the G League with Maine and Westchester.