Rafael Must Earn Louis Van Gaal's Trust at Manchester United After Injury

Rafael had run into Louis van Gaal once before the Dutchman took over at Old Trafford this summer.

The Brazilian full-back was 19 years old when he lined up against Van Gaal's Bayern Munich in the second leg of the Champions League quarter-final at Old Trafford in 2010.

It was only Rafael's second season in the Manchester United first team, and he was still trying to prove he could be consistent and dependable as well as quick and enthusiastic.

But that night in April 2010 did little to help his cause. He lasted just 50 minutes, sent off after picking up a second booking for a needless challenge on Franck Ribery.

It contributed to United's exit, and Rafael only appeared once more that season.

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He had to win back Sir Alex Ferguson's trust after that. His natural talent has never been in question. He's got pace and an attacking instinct found in all the great full-backs.

However, he has always been prone to lapses in concentration. He can get pulled out of position or provoked into a rash challenge.

When he keeps those mistakes to a minimum, he's one of the best attacking full-backs in the world.

During the 2012/13 season, when United wrestled the title back from Manchester City, he was unlucky to miss out on a place in the Professional Footballers' Association (PFA) Team of the Year. He was that good.

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Ferguson retired in 2013 with Rafael as United's undisputed first-choice right-back. It had taken a bit of time, but he had won back his manager's trust.

Like so many United players, Rafael suffered a dip last season. Injuries didn't help, his stop-start season ending in March after damaging a hamstring in a 4-1 win over Aston Villa.

Just 12 months after his most successful season at United, Rafael finds himself in a familiar position. He's got to impress his manager and cement his place in the team all over again.

His job has been made more difficult after picking up another injury during the pre-season tour of the United States.

While Van Gaal was busy assessing his squad, Rafael was back at Carrington nursing a groin injury. Finally fit again and in contention for a place in the squad to face QPR on Sunday, the hard work has begun.

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At his best, Rafael should to hold down a regular place regardless of whether Van Gaal is planning to stick with 3-5-2 or switching to 4-3-3.

The issue, as it was four years ago, is trust. Van Gaal has put his faith in the dependable, if unspectacular, Antonio Valencia so far this season.

Rafael is a better player, but he has to prove himself to be just as trustworthy. Only then will he become a regular name on Van Gaal's team sheet.

Van Gaal saw Rafael at his worst in that Champions League tie in 2010. He has improved greatly since then. He's more experienced and mature. His job now is to show it.