This is Dak Prescott's team, for good or for bad, until Romo gets back (if that even happens.) They should try and sign a veteran back up as cover for Prescott, not as competition. Anyone coming in at this stage in the proverbial game is going to have to learn the offense. No way they will be more effective than Prescott who had the entire offseason to learn the offense and get comfortable with the receivers. The Matt Cassel experience from last season should be instructive on what happens when you bring someone in at the last minute and ask them to take over with very little time to prepare. Hopefully they learn from that debacle and roll their dice with the rookie. The offensive line and running game are going to make life a lot easier on him and give him every chance to succeed without putting too much pressure on him. From what I've seen so far, I like his chances to be above replacement level, which is more than you could say about Cassel, Weeden or Moore last season.
As for Romo, while this injury may not in and of itself end his career, I think it's basically a death knell. His body is breaking down and that is not getting any better. That fact surely plays into the game planning and play calling when he's in the game. They aren't going to roll him or call for a ton of 7 step drops if they're worried about him getting hit and injured. Also, his contract numbers are pretty brutal going forward. At some point, the front office is going to have a difficult decision to make given his age, injury history, physical limitations and salary. If Prescott plays well, I think it's hard to see Romo as a Cowboys player next season absent a pay cut. Much to Bosoxen's chagrin, I've been a longtime Romo defender and I am bummed for him regarding this injury and what it means for his career as a Cowboy. He's been a fantastic QB for this franchise and really has received an unfair amount of crap as a player from fans and detractors about his track record. As a longtime Cowboy fan, I finally have some optimism for the QB position going forward (I also have a corresponding sense of dread on how that optimism will get brutally destroyed in the next several weeks.).