"He's back on his feet - he's in a running program.
"He's had another minor surgery the other week to clear up a bit of scar tissue, which then again sets him back a little bit but it had to be done.
"We've got our fingers crossed for him and we're really willing him along and doing everything we can, but it won't be in the short term."
Griffin said the operation was a case of short-term pain for long-term gain for Yow Yeh.
"I suppose it was something that had to happen for him to keep progressing," he said.
"With the extent of the injury he had, it wasn't an uncommon thing.
"The surgeons were not unhappy with it. It was just a clean-up that needed to free him up a little bit more.
"I'd hope that at some stage, he'd be able to play in the first half of the season, but it's very complicated.
"We just have to keep working with him and see how he goes."
Meanwhile, Griffin said Broncos backrower Corey Parker was back in full training after avoiding off-season surgery on the knee complaint he suffered in 2012.
As back-up for Yow Yeh, the Broncos had welcomed back winger Denan Kemp from the Dragons on a one-year second tier deal.
He was a free agent after St George Illawarra decided not to re-sign him.
- AAP
