With a talent like 30 million pounds signing Dimitar Berbatov failing to fill the void at Old Trafford, what hope is there for England if their number one striker falls victim to injury again in South Africa in June?
Rooney's magnificent season was spearheading United towards a possible treble but one tweak of his ligaments ended their Champions League hopes and severely dented their chance of retaining the Premier League title.
"Manchester United are not the same team without Wayne Rooney," Chelsea manager Carlo Ancelotti said after his team went back to the top of the Premiership with a 2-1 win at Old Trafford at the start of the month.
"Rooney is a fantastic player who is difficult to replace with another player. Berbatov is a good player but Rooney is totally different.
"Rooney can sometimes come back to receive the ball and use it for all the team and then he can attack in any direction. He is an unbelievable player. Rooney and Berbatov have different characteristics," added the Italian.
Ancelotti's compatriot Capello could say the same for Peter Crouch, Emile Heskey, Jermain Defoe, Carlton Cole and Darren Bent, who also offer different characteristics and alongside Rooney they give England a variety of attacking options.
Crouch's international scoring record - 18 goals in 36 matches - is comparable with the best in the world and he also offers a hold-up role as well as possessing an eye for a pass.
Heskey may struggle for goals but, as he showed regularly alongside Michael Owen, he makes space and opportunities for others.
PROLIFIC SEASON
Defoe is an instinctive finisher, Cole has pace and aerial talent while Bent has proved the critics wrong with a prolific season for a struggling Sunderland.
Even Fulham's Bobby Zamora could be in the mix for the World Cup squad after his impressive season but the idea of any of the lesser lights leading the line will hardly strike fear into opposition defences and could leave long-suffering England fans facing up to another early tournament exit.
Rooney was clearly feeling his twisted ankle when he made his ill-advised early return for United's Champions League second leg against Bayern Munich and he sat out Sunday's goalless draw with Blackburn Rovers having also missed the Chelsea defeat.
He could return against Manchester City on Saturday though Capello would rather see him in the stands, leaving just three more league games to limp through before the Premiership season ends on May 9.
Four years ago Rooney broke a metatarsal six weeks before the World Cup and though he missed the first group game he played in the next four matches, his involvement ending prematurely when he was sent off for stamping on Ricardo Carvalho in the quarter-final defeat by Portugal.
With England's first 2010 World Cup game against United States scheduled for June 12 there is no reason why his ankle should not be fully recovered and Capello has no need to risk him for the May friendlies against Mexico and Japan other than to maintain match sharpness.
