If Nole has tendonitis, he will be out for weeks, if not months. Won't be able to train, practise weight lift etc which will undoubtedly effect his performance when he returns to the tour.
If Nole has tendinitis that badly he wouldn't have been able to play at all, so I'm optimistic that, unless the second MRI scan shows anything more serious than the first one did, he'll be back in the foreseeable future, although there is a possibility he might be advised to skip the entire clay court season, and having had this condition myself on three occasions (right elbow twice, left shoulder once) I reckon I do know what I'm talking about.
You don't win matches without the hard graft that goes on behind the scenes. Andy has missed these tournaments in order to put in the hard graft.
He looked exhausted during the second set against Nole, leave alone what he looked like against Foggy.
I've felt all along that Andy came back too quickly and should have left it until after the AO, particularly as I recall Lendl saying that he had really pushed himself in Miami and had felt tired for most of the time he was there, so is it any surprise he was exhausted and now needs to take a four week break from playing competitively? MC wasn't on his agenda anyway because he knew he would have to play in the DC tie against Italy first and was well aware that his body probably couldn't cope with playing so much tennis at this stage of his recovery.
Andy wouldn't advertise it, but it's possible one of the reasons for this "break" and staying in the UK is so he could see his back specialist, check that everything really is fine, and perhaps work on some new exercises to strengthen it specifically for the rigours of clay.
I'm sure a six month check-up would have been on the cards, and also Andy did say that he intended to use part of his time off doing some of the more rigorous training he had been unable to do in Miami. However the fact that he's been seen regularly practising on clay at Wimbledon suggests that all is going well, although as Andy himself said recently, perhaps not quite as well as he thought it might - but then again maybe his expectations of a full recovery so soon were unrealistically high? That, of course, is pure speculation on my part, because I've never had to have back surgery or indeed surgery on any of my joints.