The 29-year-old Socceroo did not train Friday with a calf complaint and will have to prove his fitness Saturday before the Reds depart for Perth.

The defender was not concerned however, and said he only missed training to undergo 'maintenance' before Sunday's game.

"No story, just maintenance so to speak. I'm fine. We will see if I'm selected to start obviously, but I'm ready to go ... there are no issues," McKain said.

"It's (calf injury) just something that occurred and it's something minor that I just need to treat to get ready for Sunday. We train tomorrow, which is our last session before the big game, but we will all be in ready to go."

Adelaide coach Rini Coolen echoed his captain's views, suggesting he chose to rest McKain as a precaution.

The Dutchman said he was confident the former Wellington Phoenix defender would be a certain starter for the clash with Perth.

"McKain (felt an injury) a little bit with his calf and we took the position not to train with him Friday ... it was better to not take the risk," Coolen said.

"More than likely he will be available for Saturday's training session and definitely available for the game against Perth."

Coolen said he had not prepared differently for Sunday's opener against the Glory due to McKain's injury, and was sticking to his formation and tactics with his captain's name on the team sheet.

"We had a team session before training this morning, a very important one, to go over our shape and tactical positions," Coolen said.

"McKain knows everything and how we want to play, and we definitely focused our team with him in the starting eleven."

McKain, who was named United's captain in August, a month after signing with the club from Saudi Arabian side Al-Nassr, is looking forward to getting the season underway.

Despite facing a difficult away trip to Perth, another club who has undergone a series of changes during the off-season, McKain said it was important the Reds look for nothing less than a victory.

"We'll go in trying to win this game, that's the goal of our team," McKain said.

"Obviously we want to have a successful season and we don't really think that any trip away or at home is something that is not out of reach for us to get three points.

"There’s going to be circumstances in games, conditions and different factors that will affect a game, but for this game we are going in confident and think we can go for three points."

After undergoing a complete revamp during the off-season, United has seen a number of departures and arrivals.

A number of star and experienced A-League and overseas players such as McKain, Bruce Djite, Zenon Caravella, Milan Susak and Dario Vidosic have joined the Reds, strengthening and adding depth to the side.

The new arrivals to coincide with the club's strong finish last season, has seen the pressure and expectations mount once again this season, with many predicting silverware at the end of the season.

McKain said the team was not feeling the weight of expectation and was more than capable of dealing with the added pressure.

"I think the media and other people have talked us up as one of the title favourites and we are comfortable with that ... we've talked amongst the group what we want to achieve," McKain said.

"Last year the club finished third and we think we can improve on that. Hopefully during the season we’ll show our qualities and we’ll be thereabouts, but every team in the league has recruited well.

"As we’ve seen in the past few seasons this league is so tight, and the little things do make a difference, so hopefully we get a little bit of luck on our way and we can be there come late March."