Johnny Manziel May be Incapable of being a Back Up Quarterback

Johnny Manziel is on a journey to reclaim his former glory. While it seems that him being graced with a "pro day" may be a step in the right direction, it still brings a concern to Dan Patrick. He puts on the nice guy act now but will it continue? Is Manziel willing to play second fiddle to a quarterback in the NFL if given a chance?