My thoughts taken from the recently completed NFC West chat:
That would make sense. Barron is best suited to play left tackle, but the Rams drafted for that position when they selected Jason Smith second overall in 2009. The Rams also drafted another lineman, Rodger Saffold, atop the second round this year. Barron would have been playing on a one-year deal anyway, and then he likely would have been gone or out of their plans.
We recently discussed on the blog why the Rams' did not draft an outside linebacker. Carpenter would help their depth at the position, assuming he would play outside in a 4-3. He also has the size the Rams might like at linebacker.