Ryan Harris thinks the in-form Usman Khawaja can play a major role in Australia's bid to retain the Ashes.

Khawaja has been in and out of the Test side and recently spoke of the instability the selectors have created by chopping and changing.

The 30-year-old has let his batting do the talking in a prolific start to the Australian domestic season, scoring a century to inspire Queensland to a win over Victoria in their opening Sheffield Shield match at the Gabba just a month before the first Test against England at the same venue.

Khawaja also scored a hundred and two half-centuries in the JLT One-Day Cup and former Australia paceman Harris can envisage the left-hander dishing out some punishment to the England bowlers in the five-match series.

He told Omnisport: "I am 99.9 per cent sure he'll be in at number three. 

"I think the selectors, captain and coach would like him in there just to give him that freedom and say 'don't worry about looking too far ahead, get in there and give yourself a chance to prove yourself'. 

"Say to him that a failure or two here and there, don't worry about it. That will take the pressure of him, he's got to perform or he will get dropped eventually, but I think this summer is a big one for him. 

"He had a big summer a couple of years ago, but was in and out for six or seven months and missed a lot of cricket. I think this summer he's started off very well and I think he'll be a very important player."

There has been plenty of debate over the Australia wicketkeeping role after Matthew Wade fell cheaply in all three of his innings in Bangladesh.

Wade also failed twice with the bat in Tasmania's Sheffield Shield clash with Western Australia, but Harris suggested he ought to be given the opportunity to show what he is capable of in the pressure of an Ashes series at home.

"Matthew Wade's last seven or eight Tests I think have been in the subcontinent," Harris stated. 

"It's difficult enough just playing over there, let alone keeping. He's been a bit unlucky, he would have loved to be playing [well] over there of course, but he'll be desperate to get another crack at playing in home conditions. 

"It's probably going to really [be based] on Sheffield Shield games, simple as that. They are talking about Pete Nevill, who has been there before, has great hands and can bat. 

"There is Alex Carey, who I saw a bit of in the winter up in Brisbane, he's got really good hands but I'm not sure he's ready quite yet. I think he's just finding his feet in first-class cricket.

"Everyone wants a [Adam] Gilchrist and it obviously helps if you have a guy who can do that, Jonny Bairstow can obviously do that, Wade can take the game apart but has not shown the best he can offer just yet. I would not be surprised if Gilchrist has had hate mail from keepers around the world!"