The Celtics exercised their fourth-year option on Sullinger, who averaged 13.3 points and 8.1 rebounds last season. Sullinger, 22, was the No. 21 pick in the 2012 draft after falling amid concerns about his back. His rookie season was cut short by a back injury, but he returned to play 74 games last season, and was selected to the Rookie-Sophomore Game.
Olynyk, who is entering his second season with the Celtics out of Gonzaga, had his third-year option picked up. The 23-year-old big man averaged 8.7 points and 5.2 rebounds as a rookie last season after being the No. 13 pick in the 2013 draft. He is a member of Canada's men's basketball team ands scored 19 points in Boston's season opener on Wednesday.
Boston also picked up its fourth-year option on Zeller who was acquired in an offseason trade with the Cleveland Cavaliers. Zeller, 24, was the No. 17 pick in the 2012 draft and averaged 6.9 points and 4.9 rebounds during his first two seasons in Cleveland.
The Celtics defeated the Brooklyn Nets 121-105 on Wednesday. Eight Celtics scored in double-digits, led by Olynyk's 19 points. Point guard Rajon Rondo, who returned after breaking his hand last month, flirted with a triple-double before finishing with 13 points, 12 assists and seven rebounds.
The Celtics (1-0) play at the Houston Rockets (2-0) on Saturday.
- Paul Palladino