Alex Ferguson's obsession with goals ruled out replacing fading Patrice Evra at Manchester United

He's a pale imitation of the left-back who once stood among the world's best

When all's said and done, Patrice Evra is the one with the backbone in the Manchester United team. On those nights when the players slink through the post-match mixed zone, studiously evading questions from all but the club's own media channel, he will generally be there, answering for the failings in the interviews which can be more spiky.

But that does not mean that Evra's work in the last four days has not blown a major hole in the logic of Sir Alex Ferguson's summer transfer business. Robin van Persie's arrival was a huge statement of intent on United's part, but was another striker really more important to United than a world-class left-back? The question hangs there, uncomfortably, even after a 2-1 win in Cluj which showed what damage Van Persie and Wayne Rooney may do.

A galaxy of striking options looks like a luxury in the week when Evra's poor positioning left his central defenders exposed to the jet heels of Tottenham Hotspur's Gareth Bale and when Cluj's Senegalese winger Modou Sougou left him grasping at thin air on a touchline in north-west Romania.

It was the BBC's Danny Mills who observed that simply checking Sougou should have been the strategy of last resort, before the 27-year-old raced up to supply a goal. "Give a foul away on the touchline. It's not an issue. Once they are past you, you are in trouble."

This is a very pale imitation of the left back who three years ago stood among the world's best. Laurent Blanc dropped him from most of France's European Championship games this summer, declaring simply that Gaël Clichy was better, in training and matches, and the strong feeling in France is that pure sentiment on the part of Didier Deschamps, Blanc's successor, has earned Evra a recall.

The two are friends, with a shared history at Monaco. Evra's performances have been average since his return and he cuts an unhappy figure with French journalists, unwilling to talk since the 2010 World Cup débâcle.

A sense that Ferguson was looking to renew at left back this summer has been hard to pin down. The rumour that Everton's Leighton Baines was being pursued as a replacement for the 31-year-old emanated from too many places in June and July to be entirely baseless, though time and again the same message came out of Everton and from the player's representatives: that no approach had been made.

The undisguisable fact was that Everton would be asking for upwards of £15m – perhaps as much as £20m – for Baines, a 27-year-old. That does not actually sound as severe a number now as it might have back then.

Events may also have conspired against United. Southampton's Nathaniel Clyne said they were interested in him but he opted to leave Crystal Palace for St Mary's instead, believing that opportunities would be more limited at Old Trafford. Fabio da Silva, loaned to QPR, is not yet at the required level, while United's decision to lay out £4m to Vitesse Arnhem for Alex Buttner, a 23-year-old who did not set the world alight in his three years there, puzzled many in the Netherlands. Buttner is back-up material for Evra, not competition.

It was the strike force which preoccupied Ferguson most this summer. The goal difference which took the title to Manchester City last season haunts a manager who has subsequently talked perhaps half a dozen times in the past few months about the need for more goals this season. Yet the 89 his side scored in the Premier League last season was their highest total since the rampant campaign of 1999-2000, when they scored 97 and won the League by 18 points.

They lost the title last term because of the 4-4 draw with Everton at Old Trafford on 22 April, a game in which Evra, in his quieter moments, will have questioned how he allowed the Everton right back Tony Hibbert so much space to cross for the visitors' first and second goals.

It might not be mere sentimentalism to feel that those kinds of calamities don't seem to hurt United's players in quite the way they used to. The story Gary Neville tells, in his autobiography, of the devastation he felt at his calamitous performance against Vasco da Gama in the 2000 World Club Cup – it was the only time he sought help from a sports psychologist – seems a long way from the current sense that a little more time as a unit will make it all click.

Evra seemed surprised to be asked about his form after the away game at Liverpool. "Patrice Evra will have to fight for his place. Patrice Evra has always fought for his place," he said recently. It's never a good sign when players start discussing themselves in the third person. The hope must be that Chris Smalling can continue to develop as a right back when he returns. He considers himself a centre half but, then again, so did Neville. A displaced Rafael da Silva may then be Ferguson's best left-back option.

Evra cautioned on Tuesday night against the novelty of Van Persie obscuring what Rooney offers. "When something new arrives and a new player comes then everyone is talking about that," he said. "But the players who were already at the club have to show they will never die." Where Evra is concerned, that seems like an especially hard challenge.