Alex Poythress, who was a rookie last year and finished the season with Philadelphia, and undrafted free agent Isaiah Briscoe are also expected to play for the team this summer.
The Sixers will compete in the Utah Jazz Summer league in Salt Lake City from July 3-6 and then the Las Vegas Summer League from July 8-17.
Harrison started last season with the Charlotte Hornets before being released on Jan. 3.
He continued to play with in the NBA’s developmental league, now named the G League, with the Hornets’ affiliate, the Greensboro Swarm, before being traded to the Delaware 87ers on Feb. 3. Delware is Philadelphia’s G League affiliate.
Harrison has averaged 0.2 points, 0.6 assists and 0.6 rebounds in two NBA seasons, both with Charlotte.
He has also combined to average 13.8 points and 3.4 assists in two summer league stints with the Hornets.