I'm the kinda guy that if it doesn't really add too much, I'd rather just avoid the confrontation or whatever. If he was a strong part and every persons role would be necessary, I'd probably ask my other co-workers what they think. Since they've been there longer they would probably know if you will be hurting and if the guy has a high word or whatever. I don't mind helping other people out, like if he is in a situation and can't do the project. But it greatly bothers me if it's just someone trying to get out of the work and lying about it.