But there is one more test to pass before the Impact captain can play in a game. He has to head some balls, the very act that caused the concussion in the first place.
"Just one more step," Arnaud said Monday. "Just a day of heading the ball and making sure I feel fine after that.
"If I get through that in the next few days, hopefully I can start getting back to being fully involved."
It was Arnaud's first practice with the team since he was injured 48 minutes into Montreal's 6-0 thrashing of Toronto FC in an Amway Canadian Championship match on May 1.
The 32-year-old headed away a Luis Silva corner kick, but the ball struck him on the top of the head and Arnaud went reeling to the ground. He crawled to the sideline to avoid leaving TFC attackers onside, and hasn't played since.
"It was weird, but stranger things have happened," he said.
He will try heading the ball in the next few days and see if the concussion symptoms return.
He won't be back in his centre midfielder's spot Wednesday night, when the Houston Dynamo visit Saputo Stadium, but he may be ready to play 10 days later against the Colorado Rapids. By then he will have missed nearly two months, or seven league games.
"I don't want to guarantee anything because it's been pushed back a few times," he said. "I feel good right now and I'm sure everything is going to be fine."
It helped that the Impact have more depth at midfield than a year ago and were able to keep winning without his energetic play in midfield. The team is in top spot in the MLS Eastern Conference at 8-3-2 despite a 2-0 loss Saturday night in Columbus.
The Nederland, Texas, native, who scored Montreal's first Major League Soccer goal against Chicago on March 17, 2012 at Olympic Stadium, was adjusting nicely to playing in the middle after spending most of last season on the right side.
Arnaud has been dazed by knocks before, but was never sidelined by a concussion.
He endured headaches and nausea, but said it could have been worse.
"It's different for everybody," he said. "You hear stories about people who have it really bad.
"I had the symptoms you get with a concussion. I haven't been on a computer in a while because that's not recommended, which has probably been a good thing. You want to watch TV. By no means was I locked in my room 24 hours a day in the dark. It was nothing like that."
Now, a return is close enough to get excited. He wanted to stay on the pitch after practice to do some extra running, but was advised against it by a trainer.
"Once you can go back to the things you can normally do and once you get back on the field, it makes you feel like yourself again," he said "The biggest relief was just to be back on the field with the guys.
"It's going to be good just to get it out of your mind. When you have this, it's all you can think about. It's on your mind all the time, every day."
Coach Marco Schallibaum was glad to see Arnaud back.
"It's a very important guy, I need him," he said.
The team has some injuries at midfield. Justin Mapp hurt a thigh in Columbus and spent Monday riding a stationary bike on the sidelines. Felipe Martins also took a hit, but is expected to be ready by Wednesday. Andres Romero (thigh) remains a question mark.
Veteran midfielder Patrice Bernier left practice early but did not appear to be injured. A team spokesman said he wasn't feeling well.
Goalkeeper Troy Perkins missed practice to attend to a personal matter.