There had been murmurings that a back issue, which Griffen managed during his last season at the Western Bulldogs in 2014, had worsened in his first few months at the GIANTS.
But GWS coach Leon Cameron was quick to dismiss those concerns.
"We couldn't be happier with Ryan Griffen. He's completed 85-90 per cent of our pre-season and he's in fantastic shape," Cameron told 3AW on Thursday evening.
"It was actually quite funny when I started to hear that, because it's not the Ryan Griffen I've seen running around and enjoying his pre-season thus far."
Griffen was part of the mega-trade deal that saw emerging forward Tom Boyd head south to the Western Bulldogs in the off-season.
Griffen, the Bulldogs' former captain, signed a four-year deal with the GIANTS to become the club's star recruit and add to a midfield that already contains Callan Ward, Dylan Shiel and Adam Treloar.
The trade between the two clubs was struck just days after the GIANTS had refused the Dogs' request for Boyd.
Cameron admitted the GIANTS had been in contact with the Bulldogs' medical staff to discuss Griffen's injury history and to gain a better insight into how to best manage his back issue.
But Cameron said that process was commonplace.
"Any players that look like coming into our football club, we do a thorough medical investigation, like all footy clubs would do. We're no different," Cameron said.
"Yes we've looked at the medical history of Ryan Griffen as well.
"We will seek that out from them (the Bulldogs) and they've been fantastic."
Cameron said the club would take a careful approach with Griffen during the NAB Challenge to ensure he was ready to go for the season proper.
"He's (Griffen) 28 years old, but in terms of a problem with his back this pre-season, I can honestly say he has not missed one session," Cameron said.
"As a 28-year-old we've got to be mindful of overcooking him in the pre-season – he's going that well."
The GIANTS have a first-up encounter with St Kilda at Etihad Stadium in round one on April 5.
