Losing the Tiger steed by Curse
 

Tiger steed gets revived if killed, but what happens when it's discarded by a curse? Can it still be revived or not?
Player A is in combat and has a tiger steed which is an item that gives him the biggest bonus.
Player B plays curse loose an item that gives you the biggest bonus.
Can player A keep the tiger steed in his hand, or must he discard it (as it's technically not killed?)