It's one thing to keep believing the manager will change his mind and give Andy a chance to impress but at some point we're probably going to have to accept that he's not in the manager's plans. Given that likely reality, there really are only two options worth considering; a sale or a loan. The other option is that he stays but doesn't feature regularly in which case he becomes a distraction, his value decreases, and we still have to pay his wages.
With that in mind, I think the best option has to be a sale with the proceeds being used to buy a replacement. Whether that's the right option or not depends on the money being offered, as well as the possible replacements that are avilable on the market -- the manager may well have a replacement in mind now who he wants to sign now, rather than risk waiting and losing out. His budget may even be such that he can only buy an adequate replacement by selling players. A loan would only be better than a sale if the offer to buy outright was significantly lower than Andy's expected value at the end of the loan period, plus any savings made on his wages and minus any potential opportunity lost to sign a replacement in the current window.
Hard though it is to estimate his future value, we can still ask whether he's likely to have much success at the club seeking to loan him and how that might affect his value. He's bound to be a hit at somehwere like West Ham, for example, given the way they play. Since they changed their style of play and brought in Ba and Cisse, could you say the same about his chances at Newcastle? Would the fans accept him back? I'm not so sure. But even assuming that he does well on loan, it's not necessarily going to result in an increase in his value. For that to happen, we really need lots of interest from clubs that are prepared to big money and it may just be that he doesn't attract that kind of interest. He could also dig his heels in and insist on a move to Newcastle and, in those circumstances, we may be forced to compromise on a lower price than we had antincipated prior to letting him leave on loan. Would that be a better position to be in than an outright sale this summer? Doubtful. So, if the manager doesn't want him, I say we sell him and re-invest in the squad now, so both the club and Andy can move on without further delay.