Dallas Mavericks star big man Kristaps Porzingis will be sidelined to begin the season as he continues to rehabilitate from surgery to repair the meniscus in his right knee, according to Mavs president of basketball operations Donnie Nelson.

The Mavs have targeted Jan. 1 as the date that Porzingis would be cleared to begin on-court activity, Nelson told ESPN.

"We're going to make sure that that's 100 percent before we put him out there, so that's going to be into the season before we are able to have him join us," Nelson said Monday on 105.3 FM The Fan in Dallas.

The 7-foot-3 Porzingis underwent surgery in early October to repair the meniscus injury that caused him to miss the final two games of the Mavs' first-round playoff series loss to the LA Clippers.

Porzingis, 25, who is entering the second season of a five-year, $158 maximum contract, missed a season and a half after tearing the ACL in his left knee in February 2018 in what ended up being his final game with the New York Knicks. He was traded to Dallas a year later, and the Mavs, in consultation with Porzingis and his representatives, opted to have him focus on rehab the remainder of that season.

Porzingis averaged 20.4 points, 9.5 rebounds and 2.0 blocks per game in his first season in Dallas.

Nelson expressed optimism that center/power forward Dwight Powell, a starter before rupturing his right Achilles tendon on Jan. 21, would be available in at least a limited capacity when training camp opens.

"We're not going to rush, we're going to do it the right way, but we're pretty optimistic that he'll be able to join us out of the gates," Nelson said of Powell, who averaged 9.4 points and 5.7 rebounds before his injury last season.