They can draft another center, guard or tackle.

A center to provide depth and, because Swanson can back up at guard, more ability to adapt to injuries.

A tackle, because Reiff can move to one of the guard spots, and right tackle is loaded with guys who can't stay healthy.

A guard to either supplant or replace Sims.

My guess is that Sims will stay signed and a draft pick will be used to add talent.

My prediction for starting offensive line:

Reiff - Sims - Swanson - Warford - Waddle

One or maybe two back ups drafted.

Why would they keep Sims?

He got better as the season went on and he stays healthy.