The 7-foot-1 inch, 10-year veteran from Minnesota ruptured his right patella tendon and suffered a patella (knee cap) dislocation in Tuesday's 85-81 win at Dallas.
He joins 7-foot center Greg Oden among Portland's front court players on the injured list.
"Joel has been a pillar of our team," General Manager Kevin Pritchard said on Portland's Web site following Friday's surgery. "He is now on the road to recovery … and (we) look forward to his return next season."
In 30 games this season, Przybilla had averages of 4.1 points and 7.9 rebounds per contest.
The oft-injured Oden underwent surgery this month to repair a fractured left patella.
Attkisson leaves CBS News, reportedly over network's 'liberal bias'
LGBT community has 'bullied the American people': Bachmann