Singh didn't say how long he would be out but said he would miss the Iskandar Open in Malaysia at the end of the October and the HSBC Champions in Shanghai the following week.
"I have been dealing with tendinitis in my forearm for a good part of the 2008 season and my doctors instructed me to rest and try to reduce the impact of the injury for the 2009 season," Singh said in a release. "As disappointing as it will be to miss these events, it is important that I follow my doctors' direction and do what is best for my long-term health."
Singh, 45, had won FedEx Cup Playoff tournament the Barclays and the Deutsche Bank Championship so only had to complete four rounds of last weekend's Tour Championship to claim the FedEx Cup and the $10 million bonus that goes with it.
He won the WGC Bridgestone Invitational earlier in August, owns 34 PGA Tour titles and has collected $60.7 million in winnings over his career.