Melbourne - Jarrod Lyle's wife says the Australian golfer is struggling through a "really scary" period in his third battle with cancer.
Lyle, 36, underwent a bone marrow transplant last December following a recurrence of acute myeloid leukemia.
"It's been 190 days since Jarrod's stem-cell transplant and we are going through a really rough patch at the moment," Briony Lyle wrote on jarrodlylegolf.com.
"I'm typing this blog on his behalf because he's not able to do it. Jarrod's not able to drive, struggles to prepare any food for himself, can't read stories to the girls and is not able to offer much help at all around the house.
"He is also starting to look like a very frail, sick person."
Briony Lyle added: "We are both very aware of the amount of drugs and medication that has gone into Jarrod's body over the years but things are starting to get really scary at the moment. It looks as if this recovery is going to be the longest and hardest one so far."
Lyle has twice beaten acute myeloid leukemia, in 1998 and 2012, and was able to return to play professional golf.
He made an emotional comeback to the golf course during the 2013 Australian Masters in Melbourne before using a medical exemption to play on the PGA Tour in 2015. He played four seasons on the U.S. tour, where he earned $1.875 million in 121 tournaments.
Lyle has since returned to Australia permanently to be with Briony and daughters Lusi and Jemma.