Is Spence's biggest weapon Thurman's biggest weakness?

I think it's been well documented that Keith is a little "soft" downstairs. He was hurt to the body against Collazo and I'm sure he was bothered by another body shot by either Porter or Garcia aswell. So with that in mind, we all know Spence's strength is in his body work. So how is one time gonna get out of the way of this? One could also argue that both Collazo and Gurrero, both lefties, had their moments against Keith, so the southpaw stance could also be another puzzle that Keith's problems here.