Manchester United and David Moyes suffered a setback last week long before Kim Bo-Kyung's late equaliser earned Cardiff a point on Sunday.
It came a full hour before the first ball had been kicked at the Cardiff City Stadium when Moyes handed his team sheet to the referee. The United manager included some star names in his team, Wayne Rooney, Rio Ferdinand and Adnan Januzaj among them.
But one was missing: Robin van Persie.
You don't have to be a Premier League performance analyst to know that United are a better team with van Persie than without him. But in an era when every pass, shot and tackle is meticulously pawed over, Moyes will be fully aware of the statistics.
When van Persie has started for United this season, they have won 67 per cent of their games. Without him, the figure drops to 43 per cent. It was a similar story last season. United won 73 per cent of their games with van Persie and only 50 per cent without him.
It's a big difference.
United are yet to win in the Premier League this season when van Persie hasn't started the game. He missed the 4-1 defeat to Manchester City through injury and was on the bench for the 2-1 defeat to West Brom at Old Trafford.
What will worry Moyes most is that van Persie has been carrying toe and groin injuries for most of the season. The 30-year-old hasn't started consecutive games for more than a month, and if that trend continues United will need to find a way of coping without him.
Moyes has Javier Hernandez—who started against Cardiff—and Danny Welbeck in reserve if he wants to continue playing with two strikers. Alternatively, he can use Shinji Kagawa or Januzaj behind lone frontman Rooney.
But while Hernandez, Welbeck, Kagawa and Januzaj can fill van Persie's place in the team, they can't replicate his contribution. He's scored eight goals in 13 appearances for United this season, but it doesn't stop there.
There's an aura about players of van Persie's quality that can't be measured with statistics. It gives opposing players and fans a lift when he's not on the team sheet and boosts the confidence of the United players when they see him in their side.
He was the difference in last season's title race, never missing a game and scoring 26 goals. But if the Dutchman can't shake off his niggling injuries, United will have to prove that, on occasion, they can win without him.