Having astounded Sir Alex Ferguson with the speed of his recovery from the horrific injuries he suffered during last season's FA Cup defeat at Liverpool, Smith now appears to have hit something of a brick wall.
The 25-year-old former Leeds man looked exceptionally tired at the end of extra-time when United squeezed through in the Carling Cup against Crewe last month and then only lasted an hour when his side were sent tumbling out of the competition by Southend.
With Ferguson believing reserve-team football does not offer the kind of physical workout Smith needs to get fit, the United boss revealed on Friday it would be a good idea for his player to go out on loan for a short spell even though he has only two currently fit strikers in Louis Saha and Wayne Rooney.
Championship leaders Cardiff have already made an inquiry, while Dennis Wise, new boss at his former club, has also suggested he would be interested in taking Smith back to Elland Road.
However, the player has informed Ferguson he wishes to remain at Old Trafford and continue the fight for a first-team place.
Smith will instead embark on a specially constructed fitness programme, devised by United's coaching staff, which he believes will be enough to push him back to the standard required at senior level.
PA Sport