The flanker has not played a competitive game this season, having suffered a shoulder injury in the pre-season win at Wasps.
He initially recovered from the problem but aggravated it in training and was forced to have surgery.
That ruled him out until the new year and Clark has yet to play during 2016.
But last season’s supporters’ and players’ player of the season now appears to be nearing a comeback.
“He’s not quite back, but he’s working really hard up in the gym,” Mallinder said.
“His strength is coming back in his shoulder so he’s getting close.”
Kahn Fotuali’i is another man who has been out of action of late.
The Samoan scrum-half hasn’t played since puling his hamstring in the New Year’s Day win against Exeter Chiefs at Franklin’s Gardens.
But Mallinder said: “He’s making good progress.
“He’s running now, but he won’t quite be fit for this week.