The 27-year-old, who has withdrawn from Denmark's friendly in Turkey on Tuesday in order not to aggravate the injury, took his place alongside the incoming Jamie Carragher for the 1-1 draw at Stamford Bridge as his regular centre-back partner had a virus. And while he felt he should have sat out that game Agger is hopeful he will be fit to face Wigan on Saturday.
"I should not have played on Sunday but Skrtel became ill and there was not much I could do. I was thrown into it," he told TV2 in Denmark.
"I have a pulled groin. It was something that should have kept me out on Sunday but it did not. I played the game.
"It takes hopefully only a few days (to recover).
"The reason why I have cancelled for Wednesday is that it is a bit early to play three days after I played 90 minutes with a groin problem."
Any suggestion of injury to Agger immediately sets alarm bells ringing as the Dane has had his fair share of problems over the last few years. However, he has forged an impressive partnership with Skrtel over the last 18 months and has played every minute of every Premier League match this season except the last 32 of the opening game against West Brom, after being sent off, and the subsequent 90 against Manchester City as he served a suspension. Agger's confidence in possession and ability to bring the ball out from the back means he has become a key part of manager Brendan Rodgers' strategy this season. But his performances over the last 12 months have already earned him recognition after he was named Denmark's Player of the Year for the second time.
"Winning this award is one of the greatest things you can achieve as a Danish footballer," said the national team captain, who first won the award in 2008.
"I'm really committed to spending all my time involved in football.
"I have to admit that there were times when I doubted that I would ever stand here.
"I have been down and out with injuries but awards like this make me want to keep going.
"It is my attitude that means I am standing in this position."