Didak, 29, will play his first senior game since round 11 - and sixth for the season - on Saturday night against the Sydney Swans at ANZ Stadium.
He has battled persistent problems with his adductor this season; first, in the pre-season, and then after completely tearing the muscle on the Queen's Birthday against Melbourne.
Thomas said Didak had the belief to still make a difference in 2012.
"He hasn't had a great run with injuries so for him to get back, he's been a vital part of our team for the past few years and hopefully he can give us some excitement come Saturday night," Thomas said.
"I think for anyone that knows Alan, he's certainly not lacking confidence. He understands his football ability, and everyone who's seen him play knows exactly what he can do.
"He's knows he's put in the hard work and now it's hopefully time for him to get some results."
Thomas missed the Pies' round 18 clash with Greater Western Sydney to allow the ankle he hurt three weeks earlier against Carlton rest.
"The week off gave it just a chance to heal up a little bit," he said.
"It wasn't bad through the weeks before that; it was just a nice chance to give it a rest and let it fully recover."
Dane Swan didn't train on Friday with just the selected 22 and emergencies taking to the field.
Thomas said Swan, who was suspended on Tuesday for drinking alcohol, was working hard to put the incident behind him after breaking a rule that was supported by the whole team.
"Dane's realised he's made a mistake, he's putting all his efforts into getting back and trying to be a part of what we're hoping we can achieve in the next few months," he said.
"The players fully support the decision and after it was made, you put all your support into helping Swanny in his training phase.
"He realises how much of a fantastic player he is for our club so we need him to be back at his best for us."
The Magpies have an enviable record on the road, and especially at ANZ Stadium where they've won their past six matches.
Thomas said the Pies prided themselves on their ability to travel well, but didn't think the fact they haven't lost at the ground since 2005 mattered for much.
"The results of the past are in the past. It's a different season, the Swans have been going different over the past few years than what they are now and are obviously top of the table," he said.
"For us, it's about going out there and trying to execute Nathan's game-plan and if we can do that, we're very confident we can get a win."
Jennifer Witham is a reporter for AFL Media. Follow her on Twitter @AFL_JenWitham
The views in this article are those of the author and not necessarily those of the AFL or its clubs
