THE thing with potential is that for it to mean anything at all, eventually it has to be realised. Connor Wickham has spent more than four years at Sunderland and, for the majority of that time, we have been told that his breakthrough in a red-and-white shirt is just around the corner. Now, as many have secretly suspected, we can confidently say that day will never come.

The decision to sell Wickham to Crystal Palace for a fee that could eventually rise to £9m - £900,000 more than the Black Cats shelled out to sign him from Ipswich Town in 2011 - was no doubt taken with a heavy heart. No one likes to admit defeat with a project that initially seemed so promising.

But it is the right decision, and will remain so even if the 22-year-old goes on to be a huge success at Selhurst Park. The brutal reality is that Wickham has had more than enough opportunities to prove himself on Wearside. That he has failed to do so under a succession of different managers speaks volumes for the way in which his career has stagnated.

Steve Bruce signed him as an 18-year-old, then judged him too raw to go straight into the Premier League. Martin O’Neill took a long look at him, wasn’t convinced by what he saw, and duly paid over the odds to sign Steven Fletcher from Wolves. Gus Poyet was ready to jettison him after a succession of loan spells, only for fate to intervene and force him to recall the striker from Leeds United for the spell at the end of the 2013-14 season that proved by far the most successful of Wickham’s Sunderland career.

Last season, under Dick Advocaat, Wickham made his highest number of starts, but his discomfort was obvious as he was repeatedly shuffled to the left wing to accommodate the arrival of Jermain Defoe. Had he remained at the Stadium of Light, it would have been a similar story next season.

The frustration of his departure is that he should have been just what Sunderland are crying out for. Muscular, athletic and with a powerful shot from inside or outside the area, Wickham is an old-fashioned number nine in an era in which players of his type are a desirable but dying breed.

Yet the nuances of his game never quite developed as planned. His touch isn’t good enough for the highest level, his positioning and reading of the play is markedly inferior to that of someone like Defoe, while he rarely bullies opposition defenders in the manner that might be expected for a player of his build.

He will be fondly remembered for his role in the ‘Great Escape’ under Poyet, with his performance in the 2-2 draw at Manchester City in particular representing a real high. A personal favourite display was the substitute appearance in an FA Cup tie at Bolton in 2013 that saw him come off the bench to cause all kinds of havoc as Sunderland recovered from a two-goal deficit to claim a 2-2 draw.

Tellingly, however, Wickham started the replay at the Stadium of Light and did nothing as Sunderland were knocked out of the cup by Championship opposition. When he finally got his chance, he was unable to take it - a fitting epitaph for his Black Cats career.