The midfielder suffered a hamstring injury while he was away on duty with the United States during the break.
Adams has been sent for an operation for the problem in his hamstring and that has come as a blow for Leeds as they fight to survive in the Premier League.
The surgery means that the United States international will be out of action for an extended period during the Premier League run-in.
Leeds will carry out their own assessments in consultation with their medical team this week when the midfielder returns to England.
However, the Whites are still trying to ascertain the length of time Adams will be missing in action for.
The 24-year-old, who joined Leeds from RB Leipzig last summer, has been a big part of the team this season.
He was expected to play a key role for the final stretch of the season as Leeds look to avoid relegation from the Premier League.
However, Javi Gracia will now be forced to deal with the issue of not having the midfielder available for a considerable portion of the rest of the season.
Wilfried Gnonto and Max Wober are also doubts for Leeds’ trip to league leaders Arsenal this weekend.
