Manchester United centre-back Smalling has started just six Premier League games this season.
He came under fire from manager Jose Mourinho earlier this season when declaring himself unfit for selection.
Marcos Rojo, Phil Jones, Daley Blind and Eric Bailly are all vying for starts in Mourinho’s two centre-back slots.
Manchester United predicted XI to face Leicester City
Fri, February 3, 2017
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Who could Manchester United manager Jose Mourinho start against Leicester City?
I feel very comfortable with all of them
But the England defender says he doesn’t have a problem with his team-mates and they are working on understanding each other better.
“In training we’re often playing with different partners and in any given game you never know what sort of forwards you’re going to be up against,” he told United’s official website.
“I think a lot of that understanding is based around our training and what we do on a daily basis but I feel very comfortable with all of them and likewise they all feel comfortable because we play with each other every day.”
Chris Smalling (top) says he is comfortable playing with any of the Man United defenders
Smalling has struggled for game time this season, making just six starts in the Premier League
Smalling says United are constantly working on defensive structure
United are set to continue their Europa League campaign this month when the face St-Etienne over two legs, while they are also in the FA Cup fifth round and reached the EFL Cup final.
It means playing in four competitions in the space of 15 days.
But Smalling says he prefers it that way.
“I prefer to play games rather than just play one game in a week and train for five or six days,” he said.
“I’d rather play, recover, have a light training session and play.
“That’s what I’d always prefer and I probably think most players would prefer that because we like to play games.
“Training every day is good and you can improve but the games are what it’s all about.”