Tires for 2002 XLS 4x4...

I need to replace my front driver tire, it's tread is getting bare. I have a GY p245/75r16 as a free replacement, but all of the other tires on my XLS are p235/70r16. Can I use this tire on my fr driver side or is this kind of mixing and matching unsafe ( kids and wife use car ). I will gladly buy a new tire but if I don't have to then great! Thanks in advance.