Steven Naismith is expected to be out of action for 12 months after having an operation to repair the damaged cruciate ligament in his left knee.
Team-mate Chris Burke is facing between four and six months out to recover from an ankle surgery.
Both players were injured during Rangers' Scottish Cup semi-final against St Johnstone last month.
The medical team performing the operations say they are pleased with how the procedures went.
Naismith was injured in the first half of Rangers' penalty shoot-out win over St Johnstone after opposition midfielder Martin Hardie landed heavily on the striker's knee.
He followed Burke, who was substituted after only seven minutes when he was caught on the right ankle by Kevin Rutkiewicz.
"I'm not leaving because I have cleared up all my doubts"
However, at the end of April, Rangers announced that the winger was nearing full fitness and was close to a return to the first-team squad.
Goalkeeper Allan McGregor is the other player on the Rangers injury list after he injured an ankle against Celtic in April.
Meanwhile, Rino Gattuso has ruled out a return to Rangers after vowing to end his career at AC Milan.
The Italian World Cup winner had pledged in 2006 to play again for Rangers before retiring.
But the 30-year-old midfielder, who is married to a Scot, is now determined to stay with Milan and captain the club one day.
MY SPORT: DEBATE
"I'm not leaving because I have cleared up all my doubts," said Gattuso, who has three years left on his current contract.
"We have had some discussion in the past few days, but I have to underline that I have never talked about money.
"I want to end my career at Milan, I will definitely remain here until 2011. After 2011, I'll see what to do."
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