Former US Open champion Juan Martin del Potro is still searching for full fitness as he battles back from wrist surgery.
Del Potro remains 14th in the ATP world rankings, despite having missed the last seven months of action through injury.
The Argentinian won the first event of 2014 in Sydney, but his year has been disastrous since and he has been out of action since retiring against Somdev Devvarman in Dubai in February.
Champion at Flushing Meadows in 2009, Del Potro had been rumoured to be eyeing a comeback at this year's US Open, but he remains sidelined.
The ATP Tour heads to Asia through the rest of September and the first week of October, with Del Potro confirming he will not be fit for action until action visits Europe afterwards.
He posted on Facebook: "I would like to take this opportunity to tell you, my fans, that although the recovery of the wrist is progressing very well, I need a little more time to reach the competitive level necessary to compete week after week.
"I worked hard to be ready to make my comeback in Asia, where I had great results last year, but unfortunately it was not possible.
"I'm going to miss my fans in Malaysia, Tokyo and Shanghai who always gave me tremendous support. I will keep working hard on my recovery to play the European season at the end of the year.
"As always, thanks for your messages!"