Usman Khawaja was "extremely disappointed" there was no room for him in Australia's limited-overs set-up despite unavailability of Steven Smith and David Warner, and has indicated that "training hard" will be a key to his return to the team's white-ball ranks.

Despite an outstanding recent record in domestic cricket and a handful of useful displays in sporadic ODI opportunities for Australia, there was no room for Khawaja in the first squad to tour under the coaching of Justin Langer. This has meant greater first-up opportunities for the likes of Shaun Marsh, D'Arcy Short and Travis Head.

Khawaja was hesitant to give away too much detail about his omission - after previously being castigated by the selection chairman for his comments - but strongly indicated his disappointment at the decision. "I was extremely disappointed in all honesty," he told RSN Radio. "I've had a lot of chats to the selectors and a couple to JL about it. I was a bit disappointed but some things you can't control, so hopefully I'll get a chance over the next year.

"At the moment, I just assume they didn't want me in the team because they just didn't want me in the team"

"I scored a lot of runs in one-day cricket for the last five or six years, especially in domestic cricket, even when I've been away, a couple of Aussie A tours, so I'm not sure there is a lot more that I can do other than keep trying to score runs and hopefully I get a chance.

"At the moment, I just assume they didn't want me in the team because they just didn't want me in the team. There's not much other than that like ... my record in one-day cricket is better than my red-ball record funnily enough and my Big Bash record ... sometimes things just don't align.

"I've had some really good chats with JL, he's been really clear about everything, and hopefully if I put my head down, keep training hard, doing all the right things that at some stage if an opportunity comes up then I'm still quite in line, talking to him and talking around. I think the door's still there, I've just got to put my head down and hopefully an opportunity will present itself."

Last year Khawaja had ruffled plenty of feathers by saying that selection policy for Asian Tests, namely his omission from the batting order on the 2017 India tour, had caused "a lot of instability in the team". He subsequently criticised the media for reporting these comments, in a radio interview with the ABC's Jim Maxwell. In recent times Khawaja has done little other than to indicate how hard he has been working, posting Instagram videos of interval training before his departure to play county cricket for Glamorgan.

Usman Khawaja plays a fine reverse sweep Getty Images

The past Ashes summer took a considerable physical and mental toll on the Australian side, something that contributed to the environment in which Warner and Cameron Bancroft chose to tamper with the ball using a foreign object while staring at a Test match and series defeat to South Africa in Cape Town. Khawaja said the international treadmill was more draining than many realised.

"I found it really draining to be honest after the Ashes, I know a few of the other guys did too," he sad. "I was really tired. It didn't hit me until it was all finished and I was like 'oh boy' it's all caught up to me. Going over to South Africa I just knew what I had to do was give it all for another four or five weeks and I'd have a break somewhat. But the amount of cricket we played last year leading into that last series in South Africa, I think I was just pretty tired from that in general and that's why I had two months off where I wasn't hitting balls, working on fitness and that sort of stuff, but staying away from the game."

"You play a five Test series and go for about two months and you just do not switch off the whole time because you're thinking about the next game, the next innings"

Langer has emphasised a higher level of fitness with the object of having physically and mentally durable players, and Khawaja highlighted some of the things that take a toll.

"It's more about the mind, you just don't switch off. I don't think people realise that when you're playing cricket and away on the tour - even in the middle of a Test series, you play a five Test series and go for about two months - and you just do not switch off the whole time because you're thinking about the next game, the next innings, what you've got to do to prepare. It's one of those things where it's sapping after a while. Four and five-day cricket is as tough as it gets.

"People don't realise that we get up early in the morning, if the game's starting at 10, we're up by 6.30-7, we're at the ground about an hour and a half, two hours before the game starts, the game finishes at 5 but sometimes can go to 5.30 or 6, we're in the changerooms until 7 o'clock, so we're spending a lot of time at the ground. Those five days, it just feels like literally living in the ground and then it's very hard to switch off because you're always thinking about what to do next and how you can do better and everything that goes with it. After a big series it really is quite draining, let alone one Test match."

Despite his absence from the England ODI squad, Khawaja said he was hopeful of an opportunity, and expressed a preference for opening the batting in limited-overs formats. "In white-ball stuff I've always opened and I love opening, getting out there amongst it at the start, while the fielders are up I can really take on the game and I really enjoy playing that role," he said.

"In four-day and Test match cricket I prefer to be up in the top order somewhere, I've always preferred to bat at three. I batted four last week [for Glamorgan] and it was actually nice to sit down there and just relax and not have to worry about being next in, which was a little bit different, but I think I prefer to be in the top four, where I've always batted my whole life."