If Olynyk accepts the offer, he'd earn a little over $4.1 million next year, per Spotrac. Himmelsbach noted the Celtics can rescind the offer but that Olynyk is likely to turn it down and become a free agent.
Olynyk enters the offseason as one of the NBA's most intriguing restricted free agents. While he hasn't taken on a massive role over the past four years, there were a few shining moments during the team's postseason run.
Most notably, the 26-year-old Gonzaga product scored 26 points with four assists and four rebounds in the team's Game 7 victory over the Washington Wizards in the Eastern Conference semifinals. He also had a pair of 15-point outings against the Cleveland Cavaliers in the conference finals.
His numbers during the regular season were more mundane, though. He averaged 9.0 points, 4.8 rebounds and 2.0 assists while shooting 51.2 percent from the field across 75 appearances, including six starts, during the 2016-17 campaign.
Olynyk played the entire season knowing his future was up in the air. In November, Jay King of Mass Live noted the center wasn't surprised when he didn't get a long-term deal from the organization.
"I didn't expect to get [an extension]," he said. "We're in a good position as a team here and got some room to do stuff in the offseason. It is what it is."
Although Olynyk displayed flashes during the playoffs that suggested he could become an impact asset, the Boston front office has placed an emphasis on salary-cap flexibility. Ultimately, the Celtics may not be all that upset if Olynyk leaves, since it would ensure they'd retain that flexibility to pursue a marque free agent.