Former Socceroo Matt Thompson had his first start back from a calf injury last Friday night in the 3-2 win over Lake Macquarie and declared on Tuesday he was right to play some part in the club's biggest-ever match.

The midfielder could come off the bench with another former A-League player, Alex Read, to give the Magpies a killer punch late.

Coach Mick Bolch was unsure of his line-up on Tuesday but said Thompson could be kept safe for a match-turning cameo.

"He was out for nine weeks with his calf," Bolch said.

"He played 20 minutes against Edgy, 20 against Charlestown, then he got through about 65 against Lakes last week.

"It's a hard one. You start him and he probably lasts 50, 60 minutes. The tempo is high and you don't have him for that last part of the game. Or do you bring him on then and hope he wins the game for you if you're still in it?

"With Ready, Zach [Thomas] and Carl [Thornton] will do a good job at the back, and Ready can come on and get into areas and create chances.

"For us, it's about being in the game after 60 minutes and anything can happen."

The strength of Maitland's squad, which also includes former Jet Nick Cowburn and ex-Mariners keeper Matt Trott, has lifted expectations of an upset. The Mariners also have a poor record in the Cup, losing two of three games against NPL teams in the round of 32.

Bolch, though, said "a lot of people are getting carried away".

"At the end of the day, they train five days a week and are professional players," he said. "We've got 11 blokes who will be working from seven in the morning to four in the afternoon, then going and playing a game.

"While we'll give ourselves every chance and rate ourselves of giving them a run for their money, they are an A-League side and they should be beating an NPL club every day of the week."

Thompson was also cautious of raising expectations.

"It's be careful what you wish for, isn't it?" he said.

"We all cheered when we drew them, but at the end of the day, they are an A-League team, so they can cause havoc if we're not right."

Bolch believed a strong start was key.

"They are going to be sharp, but if we stay with them that first 25, 30 minutes, when the tempo is high and we can get some belief, anything can happen," he said. "We have got a good group and there's plenty of experience in there, so as long as we keep our composure and shape early, anything's possible."

As well as the Cup clash, Maitland have a hectic schedule in the NPL as they look to rise up from fourth spot with catch-up matches.

"We've got four games in 10 days, so it's a massive period coming up," Bolch said.

"But it's all about tomorrow night. Everyone is buzzing and wants to be involved in it.

"Thommo and Ready, if they are on the bench, they are going to be disappointed. They have played at the highest level and everyone wants to start in these games.

"But we'll come out with a few surprises and hopefully we're in it long into the game."