Denis Irwin remains convinced Luke Shaw will be a big star at Manchester United . Irwin , one of the most decorated defenders in United 's history , tipped Shaw to star for United shortly after he signed for the club , but the teenager has had a mixed maiden campaign so far . Shaw has impressed on a few occasions , but injury has prevented him from fulfilling his potential . VIDEO Scroll down to watch Denis Irwin : No doubt that Luke Shaw will be a top United player . Luke Shaw tussles with Alex Oxlade-Chamberlain during Manchester United 's FA Cup clash defeat by Arsenal . The former Southampton defender has failed to replicate his form for Southampton last season . The 19-year-old was made to train on his own after turning up to pre-season out of shape and he was then hit by hamstring and ankle problems . The left-back has started just 12 Premier League games so far , but Irwin is sure the club will start seeing a return on their £31.5million investment once his injury troubles are over . ' I have no doubt he will be a great player for us in years to come , ' Irwin told Press Association Sport . 'Until he gets a run of games I do n't think you are going to see the quality Luke Shaw can bring to a side . 'When he gets that under his belt you will see the best of him . 'Hopefully he will stay injury-free for us for the rest of year and get a run of games . ' United beat strong competition from Shaw 's boyhood club Chelsea to sign the defender from Southampton last summer . Denis Irwin played for Manchester United for 12 years between 1990 and 2002 . Shaw jokes about with Marouane Fellaini during a United training session last week . Irwin believes it is unreasonable to expect too much too soon from a player who only made his Premier League debut in November 2012 , regardless of how much United paid for him . 'He has had a big couple of years , ' said Irwin , who played 529 times for the club . 'He had a couple of years at Southampton , he had a big-money move here and he was involved in a World Cup at just 18-years-old so the spotlight has been on him through no fault of his own . 'When you are 19 you will make mistakes and you will learn from them . ' I have no doubt he will be getting plenty of advice from the coaches and the manager . ' Shaw , who has been suffering from another hamstring injury recently , sat out United 's 3-0 win over Spurs on Sunday . The win tightened United 's grip on fourth place and they now sit just two points behind second-placed Manchester City . Irwin ( left ) celebrates with Roy Keane and David Beckham after scoring a penalty against Liverpool in 1999 . The long-time United left back slides into a challenge with a young David Dunn against Blackburn in 1999 . Irwin was impressed by the performance against Spurs and he now hopes the team will produce similar performances against their top-four rivals in the coming weeks to secure the Champions League football which they have missed so dearly this term . 'It was a big loss for us when we did n't qualify for the Champions League . It 's been a strange year , ' said Irwin , who was part of the team that won the trophy in the most dramatic fashion in 1999 . 'We have missed Champions League football , I have missed big teams coming here . 'There are some big matches coming up in the round of 16 . We are not involved and it 's not nice watching . 'City go to Barcelona this week and we watch that and wish we were part of it because it 's the best club competition in the world . ' Denis Irwin was speaking at the launch of bwin Manchester United Casino - the world 's first club-based real money casino app which is available now on Android from bwin.com/manutdcasino and will be available soon on iOS through the App Store .
Luke Shaw joined Manchester United from Southampton for £ 31.5million . The 19-year - old has struggled for form since his move to Old Trafford . he has also battled injuries preventing him from getting run of games . robin Irwin played for the club for nine seasons between 1996 and 2002 . The 49-year - old remains convinced that Shaw will be a great player . CLICK HERE for all the latest Manchester United players .