The Sky Sports pundit believes the Saints are limited by one key factor this season.
The South Coast side's squad depth, however, is what stops them from competing with the big teams, according to the Sky Sports pundit.
Indeed, ahead of their Premier League clash with Manchester United, the 36-year-old believes the Saints don't have enough in reserve - especially in light of recent injuries.
"We’ve always said from the start that Southampton’s first XI will give anyone in the league a game. I’m a big fan of theirs, they’ve got great pace, strength and ability in the team they’re organised," Carragher wrote in his regular Sky Sports column.
"They’ve got a lot of things going for them but where they can’t match the big teams is in size of squad and quality of payer in reserve and when they do have injuries it will tell.
"They’ll be missing [Morgan] Schneiderlin, who I think is a fantastic player, [Toby] Alderweireld come off the other night and he’s a good player as well so when they do get injuries that’s the problem for the so called ‘lesser’ clubs."
Southampton host Manchester United at St Mary's on Monday night.