It all depends on how much was 'physical decline' and how much was mentally clocking out for whatever reason.
If it's the former, then you'd think he'd continue to struggle anywhere. If it's the latter, then it depends on the reason why he mentally clocked out here. If it's to do with overall attitude, lifestyle and priorities, etc, then, again, those will probably rear their head wherever he goes. If it was an ongoing problem he had with the club, and a change of environment will change that mental process and see an increase in effort and desire, then he's likely to perform much better for as long as that change of attitude lasts.
His purple patches have never lasted too long here - even before the dramatic decline he was prone to inconsistency. Just not as low lows, and for as long, as we've witnessed in recent years.
So it's anyone's guess really. My guess, for what it's worth, would be he'll put in more effort in his short loan spell - but wherever he ends up permanently, his form will continue to be patchy and examples of off field issues / questionable effort will occur again either side of some purple patches.