The Leeds United attacking midfielder has spearheaded the club's automatic promotion pursuit this season and has been one of the best players outside of the top flight.
The 27-year-old defender has made 34 appearances in all competitions during the current campaign, and is a key figure for the Whites.
Leeds United winger Jack Harrison has insisted that the Whites play their best football when they are not anxious about other results in the Championship, following the advice head coach Marcelo Bielsa provides.
Saturday was a big day for promotion-chasing Leeds United.
When asked if the injury was serious, Bielsa told Leeds Live: "We don't think so because he felt like a muscle strain".
"I used to play the game but sitting on the other side now as a fan, all you can do is applaud him sometimes for what he does with the ball. It's important to know he couldn't play the game".
Leeds now have four games to play to clinch a place in next season's Premier League, starting with next Friday's game at home to Wigan Athletic.
Bielsa's side now have a three-point cushion over third-placed Sheffield United, and having Cooper available is a massive boost for their automatic promotion hopes.
Harrison joined Leeds last summer on a season-long loan deal from Manchester City.