Would a frag grenade go off in your hand in this situation?

So say some dumbass enemy pulls the safety pin and lobs a frag grenade at you, but forgets to flick off the safety clip that goes over the spoon (or clip, what ever you wanna call it). If you then hold the grenade like you would if you were throwing it, and removed the safety clip to throw it back, would the grenade explode in you hand? or would you still have the time to throw it?