While the Reds are still favourites to retain their Premier League crown, doubts are beginning to emerge.
Van Dijk could be out for the entire season after undergoing surgery on a knee injury he picked up against Everton.
The Merseyside derby ended in a draw, but the Reds come off far worse, losing their defensive talisman.
"The big question you're looking at now is, can Liverpool win the league without Van Dijk there? I think every team has three or four players in every title-winning team or a team who think they can win the title, and if one of those players is missing, no matter how good your manager is, no matter how big your squad is, you can't cover for them because they're outstanding," said Carragher on Sky Sports.
"I think it blows the title race wide open, I really do.
"I still felt at the start of this season Liverpool were the team to beat. I think with Van Dijk being out for what looks like the whole season now, I think it's going to be all on for Liverpool. I think Liverpool certainly have to go into the market in January, and not just because of Van Dijk's injury, but Liverpool were weak in that area anyway. They lost (Dejan) Lovren before the start of the season now the other players in those positions are very injury prone.
"Yes, devastating news for Virgil van Dijk - we pass on our wishes and I'm sure everyone does around football - but I think for Liverpool, Jurgen Klopp and the club now, right away it's who can they get in?
"I know the transfer window has just finished but they have to be ready on January 1 to bring someone in because they are really weak in that area and that could stop them going on to try to achieve what they want to achieve."