It all depends on what other centers are out there. Mangold > Barnes but is much older. I think he would be an instant success as a short term option. Barnes issues have always been strength. Mangold is not so easily pushed around.
How many years could the Rams get out of him?
Also, in one of McVay's interviews while mentioning a few of the Rams players, he threw Barnes into the group. Does that mean he liked what he saw? Or just throwing out names on top of his head?