I seriously doubt TJ can make 125. It's just a bad idea all around for three strong reasons:
1) TJ won't have an interest in defending the belt if he wins, he will want his next fight to be at a weight class above his belt. Enough of that crap.
2) If TJ misses weight, the right thing to do would be to scrap the fight. DJ deserves his next fight to be a chance to break the defense record. I hate scrapping fights.
3) As the most dominant champion EVER (Cmon, let's be honest with ourselves and agree that DJ never turned in stinkers of performances like Silva has multiple times) DJ definitely deserves to call the shots. TJ needs to earn his shot at 125, and being a TUF coach against someone with the bantamweight belt who gets injured doesn't earn shit.
We can all agree that Ray Borg is not the ideal candidate for a title shot at 125, because no candidate is ideal. Borg has missed weight twice in four fights, and is only on a two fight win streak. He is not a complete mixed martial artist and would be a serious underdog against DJ. However, literally every other 125lber is a worse option, mostly because they are coming off losses or have lost to DJ in recent memory (or have lost too many times in their careers against DJ).
The only problem with DJ taking the Borg fight is, what do you do with TJ?? It's a TJ problem, and while it should be easy enough to say "too bad, so sad, your prob and not mine", I actually have a good solution:
Book TJ v Dodson 2, have it timed well for Mouse v Borg. The UFC LOVES rematches, so this should be an easy decision for the matchmakers. I'll go so far as to say TJ deserves a good matchup that would make him some money, and a chance to avenge the TKO loss has got to be almost as appealing to him as a chance to avenge his loss to Cruz.. but it makes more sense with Dodson coming off a win. If TJ really REALLY wants to fight at 125 and challenge Mouse for the belt after a flyweight win, throw an extra 20k at Dodson to make it a 125lb fight, he'd probably be down. However, I think the right course of action is TJ v Dodson at 135, winner fights Cogar. Worst case scenario if Cogar is out for too long, TJ/Dodson winner fights the winner of Cruz v next opponent.
So there you have it - DJ v Borg is perfectly fine, TJ should fight JD instead of DJ. All is well in the UFCverse, except Cogar's back, since it's still injured or something.