Former England stars Will Carling and Jeremy Guscott were among those who questioned Farrell's continued place in the Test team, but many - Gaffney included - felt the criticism was unjustified.
Farrell has been included in a 28-man England training squad to prepare for the Twickenham appointment with Six Nations favourites France on Sunday week, with head coach Brian Ashton set to announce his line-up next Tuesday morning.
Gaffney said: "Andy is looking forward to playing this weekend.
"He has trained well this week, and with a real buzz as has the rest of the squad."
Saracens, beaten just once in the Premiership since late November, should continue their title play-off push by defeating a Sale side again shorn of key players through injury.
Although centre Elvis Seveali'i and prop Andrew Sheridan return to the starting line-up, England pair Jason Robinson (neck) and Magnus Lund (concussion) are sidelined, while long-term absentees Charlie Hodgson and Jason White are in America for further rehabilitation on knee problems.
But Gaffney added: "Sale are a very good side, and although they have injury problems, they are starting to get a number of those players back. They have quality throughout their squad."
Wing Tevita Vaikona, prop Kevin Yates and former Ireland hooker Shane Byrne all gain call-ups for Saracens, with Sale's league away form this term - six defeats from eight starts - suggesting a probable home win.