Guillen is still recovering from a deep bruise on his left knee that ended his season last August. He hasn't played in any Grapefruit League games this spring.
Zumaya is recovering from surgery to his right arm and hasn't pitched since last June.
Leyland refused to speculate Tuesday on when Guillen or Zumaya might return.
Leyland also says the Tigers sent top pitching prospects Andy Oliver and Jacob Turner to the minors, along with 16 other players including his son, minor league prospect Patrick Leyland.
Information from The Associated Press was used in this report.