Canning, who came on at half time for his first appearance of the year, found the net with his first touch of this Walsh Cup tie, but was then forced to retire on 67 minutes with manager Anthony Cunningham fearing the worst.
Cunningham said: “It’s dislocated and maybe even broken. Injuries are awful hard this time of year. Guys are coming back from one injury and going into another one.”
Galway bossed the game from start to finish with Jason Flynn hitting 1-4.
Despite Sean Ryan opening the scoring for Offaly, it wasn’t long before Galway asserted their dominance and commanded a 0-5 to 0-2 lead after 10 minutes.
That advantage grew in the 13th minute when Jonathan Glynn set up Forde for a goal (1-6 to 0-2). Galway were in ruthless form and David Collins finished off four scores in a row for Anthony Cunningham’s side after 21 minutes. Shane Dooley saw his penalty saved by Colm Callanan before Galway eased into a half-time lead of 1-17 to 0-5 with Jason Flynn and Dean Higgins popping over the pick of the scores.
Offaly recovered somewhat on the restart but not before half-time substitute Canning found the net for Galway’s second goal.
Shane Dooley netted for the hosts with 20 minutes to go but by then, the game was over as a contest, as Galway led 2-19 to 1-7.
Offaly manager Brian Whelahan was left unimpressed: “I’m very disappointed. Today was a day where you would want to be showing the work that you have been putting in. It was a disappointing 70 minutes.
“We have worked very hard over the past two and a half months addressing those things, but it didn’t happen today.”
Scorers for Galway: J Flynn 1-5 (0-4 frees), D Higgins 0-5 (0-1 ‘65’), J Canning 1-0, P Brehony 0-3, J Glynn, A Smith, D Collins 0-2 and J Cooney 0-2 each, E Burke 0-1.
Scorers for Offaly: S Dooley 1-3 (0-2 frees), S Quirke 0-4 (0-3 frees), S Ryan 0-2, C Kiely 0-2 (0-1 S/L), G Mann and S Kinsella 0-1 each.
GALWAY: C Callanan; D O’Donoghue, F Moore, P Mannion; C Flynn, D Collins, G McInerney; J Cooney, A Smith; P Brehony, J Glynn, D Higgins; E Burke, J Flynn, B Molloy.
Subs: J Canning (for E Burke H/ T), J Coen (for D Collins 47m), J Regan (for B Molloy 47m), P Kileen (for J Glynn 57m), P Hannon (for J Forde 63m)
OFFALY: J Dempsey; P Camon, D Shortt, S Egan; E Nolan, C Egan, C Parlon; S Ryan, S Wynne; T Carroll, D Currams, G Mann; S Dooley, S Kinsella, S Quirke.
Subs: N Wynne (P Camon 27m), C Kiely (for S Wynne 29m), D Mooney (for E Nolan H/T), E Murphy (for C Parlon 54m)
Referee: J McGrath (Westmeath).