The Latics skipper has appeared just once since the start of April but is prepared to make himself available to give Roberto Martinez's men every chance of bridging the gap on the three clubs who sit five points clear of the drop zone.
"All you can do when you're out of the team is keep working hard and being ready for when the opportunity arises again," Caldwell told the Wigan Evening Post.
"Everyone in this squad has a massive role to play between now and the end of the season.
"Everyone has to be ready for when the gaffer decides it's right to go in, and that's definitely the case with me.
"We're looking at every game between now and the end of the season as one we have to win, and we believe we can do that.
"We've been down there and managed to get out of it for the last few years, and we're bracing ourselves for it going all the way again.
"It's in our hands, and we have to have a real belief that we can still get out of it."