The 30-year-old centre-back had been missing since early December with a hamstring injury, but was back in the line-up for the Latics trip to Goodison Park.
And, despite Caldwell inadvertently directing Leon Osman's opener past Ali Al-Habsi in the loss to the Toffees, Boyce is confident his team-mate will improve Wigan's solidity.
"It was great to have Gary back in the team because he is our captain and a vital body in defence that has been missing," the Barbados international told the club's official website.
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"We're close to having the whole squad fit and we're going to need that as we get further and further into the second half of the season.
"We're frustrated at the moment because we can't get stuck in a rhythm of performing well but not getting the results.
"Sooner or later we need to start picking up a good series of points because we have to be aiming to look at getting above teams rather than worrying about teams below us.
"We're confident that the situation can change because we've done it before.
"If we can create more chances and take them then I'm confident that the rest of our game is good enough to win the upcoming matches."