The 22-year-old has been struggling with a hip injury, and as a result is not expected to return to club action for at least two weeks.
"The various physios have spoken to each other and there's no issue between us," BBC Sport quotes Lambert as saying. "I know the country has the right to have their player when they're together before an international so that's it.
"I worry about every one of my players and injuries when they're away for their countries."
The Midlands outfit will travel to Hull City in the Premier League this weekend.