Gaffney tipped Hill to shine for England in the World Cup in France later this year after seeing him star for Bath.
"I've no doubt about it," said Gaffney, after his side's 20-20 draw at Bath.
"You've only got to watch his games and the way he's been playing for the last couple of weeks. He has been outstanding.
"It's not just what he does on the track but his persona in the team.
"He may not have all the pace he had but the intelligence is there," added Gaffney.
Hill has missed a number of England matches having spent 18 months out of the game with to undergo succession of operations on his knee.
Gaffney added: "He still going through his rehab, it's fantastic the way he trains and amazing the way he's playing, where he's got to.
"At the moment it's a man management thing and we speak every day about it."
Bath head coach Steve Meehan was not so happy with his players, despite snatching a share of the Guinness Premiership points with a late try at home to the Sarries.
"We should have won that game but we were the victim of two poor decisions by our players and one by the ref for one of their tries," claimed Meehan.
"We've had very good preparation this week but the lack of skill execution by us today caused us problems.
"We have had the same players making the same errors all year."
Bath snatched a draw three minutes from time with a David Bory try converted by Olly Barkley.
Saracens looked to have secured a vital away win up to that point after coming back from 13-0 down with tries from Hill and Tomas de Vedia.
Barkley gave Bath the lead from an early penalty and repeated the does after 10 minutes and the then converted Chris Malone's try.
Tries from de Vedia and Hill were converted by Glen Jackson before his penalty extended the lead.
Jackson kicked another penalty before Bory's try and Barkley's conversion tied it at 20-20.