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Manchester United spent most of the summer transfer window aggressively pursuing Leighton Baines.

Numerous bids were lodged, but none came close to the Toffees' valuation, leaving the England left-back to continue his seventh season in Everton colours.

With January's transfer window now on the horizon, rumours are already circling about a renewed bout of courting, with John Richardson in The Express among those insisting a deal is close.

According to Sam Wallace of The Independent, Baines' personal preference was to join the Premier League champions, but—if true—this is an urge he should now suppress, at least until next summer.

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The primary reason to stay put is the 2014 World Cup.

Despite an ordinary start to this current campaign, in club terms at least, there’s a loud crescendo of support finally recognising Baines' ability and lauding his play.

For the first time in a decade, Ashley Cole’s name isn't such an instinctive inclusion on every England team-sheet.

Many consider Baines his equal and in with a genuine chance of starting, with Roy Hodgson open about the fierce competition at left-back.

While a move to the Premier League champions should theoretically boost Baines' claims further, he's never been natural with change or especially quick to acclimatise.

With both Everton and England, he’s needed substantial time to bed in and feel he belonged, which is why a major transfer so soon before the World Cup would be a huge risk.

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His first season at the Toffees was punctuated by lengthy stints on the bench. He was unable to dislodge Joleon Lescott, who was playing as a makeshift left-back, and seemed hesitant and uncharacteristically erratic when on the field.

Baines started just 13 of 38 Premier League games, coming on from the bench nine times and even played a few games in left midfield.

From starting just 34 percent of the Toffees' season, he was far more prominent during his second year, starting 26 games.

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He began to establish himself far more during that second season but required all of this time to feel completely comfortable, such was the obvious pressure his £6 million transfer fee brought him.

Since those first two years, in which he started just 39 of a possible 76 games—completely missing 23—he's only missed six Premier League games in four seasons, and only because of injury.

He's been Everton's best player for most of that time, winning Player of the Season awards in 2010, 2011 and 2013, but there's little doubting the substantial adaptation period he needed after joining.

Baines admitted as much to Daniel Taylor, in a piece for The Guardian back in 2007, highlighting his occasionally fragile confidence.

I've always struggled in terms of self-confidence. I was desperate to join Everton but, once everything went through, I worked myself into a bit of a state. I was worried that it would be really hard to settle in, that my face might not fit. And I was worried about what the established players would think of me. I thought they would look at me and wonder what the hell some lad from Wigan Athletic was doing there.

Baines goes on to reveal his worries at gaining promotion to the Premier League with Wigan, feeling sure he would spend the entire season in the reserves.

The level Baines has now reached must erase large portions of this doubt, but there's also been recent evidence of these nervous traits on the international stage.

The 28-year-old has been fully established in the Premier League for some time—named by his peers in the past two PFA Teams of the Year ahead of Cole—yet, while his domestic form warrants international inclusion, his England form has only recently earned such rave reviews.

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He made his debut back in 2010 but—on the rare occasion he made the field—suffered with inconsistency, similar to his early years at Everton. To be fair, England seldom used him in the same attacking way the Toffees did, limiting his value, but he rarely produced an unblemished showing.

His appearances prior to World Cup 2010 didn't do his ability justice, especially a final friendly against Mexico, and he eventually missed out on selection for South Africa.

Stephen Warnock won the race to deputise for Cole, with Baines' omission possibly linked to a few poorly timed quotes about homesickness issues—another sign of his struggle with change.

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Wherever he goes, Baines is clearly a player needing a generous amount of time to settle in, something Manchester United are as unlikely to provide as anyone.

There's nothing to say Baines wouldn't eventually become a success with United, but playing in front of an expectant crowd of 75,000 would be an unnecessary challenge at this particular juncture—as Marouane Fellaini is demonstrating perfectly.

He cannot afford to suddenly be in and out of the team, spending time on the bench and losing his rhythm. To make the World Cup, he must be starring every weak.

Every step of Baines' career suggests a January move to Old Trafford would be unwise. It would disrupt his consistency and potentially derail his growing chances of starting in Brazil.

If he makes any club commitment before the World Cup, it should only be a contract extension to help quell the incessant speculation.

The year 2014 will be the most pivotal of Baines' career. He will go to a World Cup at the peak of his playing powers, and faces the biggest decision of his club career.

Any move to prioritise his club status and move in January would be an unnecessary risk, and one he could regret for the rest of his career. He must go to Brazil as an Everton player.

Follow @Matt_Cheetham