The tell-tale signs are there. Eyes constantly darting sideways, a foot tapping up and down, hands fidgeting with a piece of paper.
Craig Foster is a hyperactive individual at the best of times. But not having kicked a ball for four months, he is virtually jumping out of his skin.
Which is good news for the Northern Spirit, who tomorrow night hope to hand a debut to the Socceroo midfielder against Newcastle United at Gosford. After four months of inactivity and over four weeks of wrangling with his former club, Crystal Palace, Foster is finally expected make his return to the national league at NorthPower Stadium.
Keep an eye on the first 50-50. Foster may well take the ball, the man, and the grass so eager is he to let off steam.
"It's been frustrating, there's no doubt about that," he said.
"I thought I would be back playing a few weeks ago but it hasn't worked out like that. Obviously I'm not match fit, and I'll probably feel it in the last 15 or 20 minutes. But I'm ready to give it a go."
Foster, 31, could well be the most important signing Spirit coach Graham Arnold has made in his two seasons with the club.
Craig's talent is one thing strong in the tackle, good distribution, plenty of stamina, and an eye for goal. His leadership qualities are another Foster talks from the first minute to the last, and on-field communication is something the Spirit have patently lacked in recent seasons.
But it is his attitude which will set him apart, and benefit the Spirit the most.
"I'm not a 31-year-old who is coming home with nothing to play for," Foster said.
"I'm a 31-year-old who is coming home to maintain the same standards I have always set myself, to make sure I give myself every chance of a second World Cup campaign."
Significantly, Craig Foster consulted national coach Frank Farina before making the decision to leave England where he played for Portsmouth and Crystal Palace and return to the NSL after a three-year absence. In an era when the Socceroos are almost exclusively picked from overseas, Foster wanted to make sure he was not closing the door on his international career.
Farina assured him good form for the Spirit would keep him in the frame. The fact that Arnold doubles as assistant coach to the national team should also ensure Foster stays in the shop window. The rest is up to him.
The indications are promising. Fully recovered from a knee injury which hampered his final season and cost him a renewal of his work permit at Selhurst Park, Foster has been training the house down preparing for his return to the field. His new teammates are still talking about a goal scored in a recent practice game, and while the Spirit have enjoyed a strong start to the season, Foster's inclusion tomorrow night will add an important new dimension.
This, after all, is a player who injury apart has been a regular member of the national team for the past four years, a player who has not looked out of place interchanging passes with Harry Kewell, Mark Viduka, Ned Zelic, Paul Okon or any of our other hyped-up stars.
Foster insists he will not drop his guard now he has returned to the NSL, and there is no reason to disbelieve him. Certainly when you appreciate how hard he worked to win the first of his 29 caps, then you accept how much playing for his country means to him. A player who made his international debut at the age of 27 is not going to relinquish his green-and-gold jersey without a fight.
Indeed, as much as he is excited about making his Spirit debut in Gosford tomorrow, he is also disappointed that he missed the plane to Glasgow, where the Socceroos will play Scotland next week. The delay in getting his clearance from Crystal Palace which should arrive today cost him any hope of a call-up, and he aims to make up for lost time.
* In tonight's only national league match, Adelaide City will again be without experienced attackers Aurelio Vidmar and Claudio Pelosi for the trip across the Tasman to play the Auckland Kingz.