Strauss returned from South Africa's disappointing November tour of Europe with a pinched nerve in his lower back and was recommended an operation to fix it.
The 31-year-old hooker is now expected back in action for the Bulls in March, officials said on Friday.
Strauss announced his retirement from international rugby after a year as captain in which South Africa lost eight of 12 tests this year but has committed to playing for the Bulls for the foreseeable future.
Combrinck, 26, fractured a shoulder joint playing for South Africa against Wales in Cardiff last Saturday and underwent surgery on Wednesday.
He will be out for around four months, a statement from the Lions rugby franchise.
Super Rugby gets underway on Feb. 23.
(Reporting by Mark Gleeson; Editing by Martyn Herman; mark.gleeson@thomsonreuters.com; +27828257807; Reuters Messaging: Reuters Messaging: mark.gleeson.thomsonreuters.com@reuters.net)
