Dado Prso will leave Rangers at the end of the season.
Prso will leave Rangers at the end of the season
The Croatian striker informed Rangers manager Walter Smith of the news after consulting a specialist about a persistent knee complaint.
Prso will not retire but will instead look for another club where the physical demands are not so high.
The 32-year-old said: "I said to Walter I am just sad I didn't get a chance to come here when I was younger and in better shape."
Prso was signed by Alex McLeish on a free transfer from Monaco in May 2004.
He retired from international football after the 2006 World Cup and is disappointed that he has now been forced to leave Rangers.
"I would have loved to play here longer," he said.
I have spoken to the coach about my decision and it was a sad feeling
"The manager knew about my situation and has seen how hard it's been this season with injuries.
"I will wait until the end of the season before I decide what I will do next year.
"I have the option of playing in an easier league, where things are not quite so intense, but I don't know.
"I am going to give my all until the end of the season and try to score as many goals as possible.
"The seasons have been getting harder and harder and I don't think it's fair to play if I am not at my peak fitness.
"I think you can see from my level now and what it was, there is a difference and that's hard for me to take.
"I aim to try and do better in the remaining matches than I have done recently and I want to go out on a high.
"I have spoken to the coach about my decision and it was a sad feeling."
Prso helped Rangers win the Scotttish Premier League and League Cup double in his first season, scoring 21 goals.
But his appearances have become less frequent this term.
Prso's agent, Rank Stojic, told BBC Sport: "The doctor advised him that if he continues to train and play with the intensity that he does at Rangers then he could damage his knee long term.
"Dado has too much respect for Rangers not to give them 100%."
However, Prso will not end his playing career when he leaves Ibrox and could join LA Galaxy-bound David Beckham in the US Major League or head to the Far East.
"He will play on for sure," said Stojic.
"We could make a decision on where he plays in the next 10 days or two weeks.
"The United States or the Far East are options he will consider."