The Raptors announced Monday that Jawai will be held out of practice because of concerns from a routine cardiac screening. The first indigenous player from Australia to be drafted by an NBA team, Jawai was the 41st overall pick in June.
Toronto opened training camp Tuesday and has 14 players on its roster.
Sampson, a five-year veteran, has played for Charlotte, Denver, the Los Angeles Lakers, Milwaukee and Sacramento. He has averaged 2.0 points and 3.4 rebounds in 72 career games. He was a second-round pick by Utah in 2002.
Ralph Sampson was a four-time All-Star and the 1983-84 NBA Rookie of the Year.