A player (or club) enjoys an impressively strong debut campaign in a new league only to suffer a slump and downturn in fortunes in their second.
That seems to be what's happened to Anthony Martial.
Signed by LVG for £36 million from Monaco and written off as a panic buy, he defied the doubters and instead proved to be the Dutchman's best purchase.
He stood out as last season's standout star, becoming an instant hero with his wonderful goal on debut against Liverpool and in a dark, depressing season, lit up Old Trafford with his pace, trickery and direct style (finishing the campaign with 17 goals).
However, this season he has found the net only twice in 13 appearances and looks very short of confidence, having failed to find any semblance of form.
Mourinho cannot be blamed for this as he stuck by the young Frenchman and given him numerous chance to turn things around but now is believed to be running out of patience.
He started the draw with Arsenal but, despite being available, was dropped for the visit of Feyenoord and looks set to remain on the sidelines for the visit of West Ham after Henrikh Mkhitaryan's outstanding performance against Feyenoord.
Jose played down his absence afterwards, insisted that Martial was rested in a simple case of squad rotation, as he has too many options to accommodate everyone.
Mourinho has also been blunt when it comes to addressing the young Frenchman's Old Trafford future: he has failed to take three opportunities offered to him by Jose and there cannot be many more.
There a number of reasons why Martial is finding life hard: a disappointing Euros in the summer, the loss of his shirt number to Zlatan Ibrahimovic (without his knowledge) and the public breakdown of his marriage, coupled with his slump in form, have certainly not helped his cause.
The Portuguese boss has suggested that a change in tempo and intensity may also have hindered his young attacker: maybe Martial was better suited to LVG's slower, more ponderous style and system and he may be struggling to adapt.
To compound his worries, strong rumours are beginning to circulate that Mourinho will attempt to entice his former player Willian from Stamford Bridge to Manchester in January.
The Brazilian is out of favour under Antonio Conte and was highly regarded by Mourinho so where this leaves Martial remains to be seen.