The Swiss defenceman was tabbed to be back to face the Washington Capitals on Saturday night after missing 25 games with a concussion.
The club had been reeling on defence since an injury to Alexei Emein on April 6, and Diaz is expected to bring his skill and puck-moving ability into his spot alongside veteran Andrei Markov.
"I did a lot of skating this week and yeah, I'm ready to play," the 27-year-old said. "Of course the game speed is different.
"I need a couple of shifts and then I'll be ready."
Diaz was a key player for Montreal through the first 19 games of the season before he was injured on Feb. 25 against Ottawa.
With P.K. Subban missing the first six games while getting his contract signed, Diaz stepped up. And even after Subban returned, the five-foot-11 Diaz was usually getting more than 20 minutes per game as well as seeing some power play duty.
That gave him a chance to show the offensive flair that had made him a star in his native Switzerand before he signed as an undrafted free agent with Montreal last season. He had a goal and 12 assists before the injury.
That should help a team that gave up 24 goals in the first six games after Emelin's season ended with a torn knee ligament, which he suffered while putting a hit on Boston's Milan Lucic. It included a three-game stretch of losses in which they allowed 18 goals.
He won't replace Emelin's physical presence, but he will help move the puck out of the zone and pick up the pace of the game.
"It's a big lift and a confidence booster for everyone," rearguard Josh Gorges said of Diaz's return. "I think he's an outstanding hockey player.
"He's a guy that does everything well for you. He'll help solidify our top six. He can play in all situations."
Diaz struggled with injuries as a first-year NHL player last season, when he had only three goals and 16 points in 59 games.
Bad luck struck again this season against Ottawa, when he was run into while falling to the ice and had an opponent's leg clip his chin.
"The problem was that I wasn't ready," he said. "I was protecting myself to fall down.
"If I saw the leg coming, it wouldn't't be that bad."
The recovery wasn't as rapid as he hoped. He wasn't able even to skate or exercise in the first weeks, but the process went quickly once he started feeling better. He has been skating for about two weeks.
It was his second concussion, after one suffered three years ago in Switzerland.
It was also a big day for winger Brandon Prust, who was named the winner of the Jacques Beauchamp Trophy as the team's unsung hero as voted by the local media.
Prust has brought much-needed physicality to the Canadiens, whose strengths are speed and team play. He is also popular among his teammates.
"It feels good," said Prust, who signed as a free agent from the New York Rangers last summer. "That's the easy part of the game for me — to go out and work your butt off.
"It's what got me here, so I knew coming in everyone in Montreal would appreciate that. It's easier for me to come in than for a guy who is expected to get 50 goals. I just do my work. It's good to see it's appreciated."
Prust has five goals and eight assists in 34 games and leads the team in penalty minutes with 104.
Gorges, who won the award last year and in 2010, said Prust earned it.
"He's the type of guy that every team needs, especially at playoff time," he said. "You need that physical presence, but in the game now, you can't just have a goon. I don't want to say that word, but a guy that all he does is fight.
"(Prust) can play and he plays very well. He can play on your third line checking, he can play on your first line to open up room and make plays. On the penalty kill, he's outstanding. He does a little bit of everything and makes everyone better when he's on the ice."
Prust finished ahead of Bouillon and backup goalie Peter Budaj in voting.
The trophy was first awarded in 1982 to centre Doug Jarvis.