The 25-year-old picked up an injury during the Gers' Challenge Cup final win over Peterhead.
Mark Warburton has admitted to Rangers' official website that it is a blow that Harry Forrester will miss the Scottish Cup semi-final clash with Celtic, but insisted that they have the quality in the squad to make up for his absence.
The attacking midfielder is set to miss the next few weeks after fracturing his leg in the Challenge Cup final win over Peterhead last weekend (via BBC Sport), meaning that he will have to watch the Light Blues take on the Hoops from the sidelines.
And while Warburton conceded that he would be a big loss, he chose to remain positive about the options he does have available.
"He's been in good form for us. He offers us flexibility. He's one of the players that can play 7, 8, 10, 11 in our formation and he offers us balance," he told the club's official website.
"So it's a blow to lose him. [I'm] disappointed for him, [it's] disappointing for the team but we've got other players in the squad who are looking forward to it, will step up and have the quality to add value to the squad."
Although their run to the Scottish Championship title has proved that they have plenty of quality going forward, Forrester's form in recent weeks would have arguably made him one of the most likely candidates to help the Gers spring a surprise.
He has scored five goals in his last nine games in all competitions, including the opener inside the first minute of the club's quarter-final tie with Premiership side Dundee. And with the Hoops promising to provide a much tougher contest, Warburton's men could have certainly done with the 25-year-old making a similar impact at Hampden Park.