Saracens director of rugby Mark McCall will take "a short break due to medical reasons," the Premiership Rugby side said on Friday.
McCall, who took on the role during the 2010-11 season, has led Saracens to five Premiership titles and three European Champions Cups during his tenure.
"People will always come first at our club and Mark will be given all of the support and time he needs," Saracens said in a statement.
"Meanwhile we would ask that everyone respects Mark's privacy. Mark is obviously more than confident in the coaching team he has worked with for many years to temporarily take the reins."
Saracens are second in the Premiership standings with 12 games played, and next face Wasps on Jan. 30.