Liverpool revealed on Thursday that their worst fears about Lucas had been confirmed, with the Brazil international ruled out for at least six months after suffering significant anterior cruciate ligament damage during his side's midweek Carling Cup victory over Chelsea.
Lucas has arguably been Kenny Dalglish's most consistent player this season and put in a particularly impressive display in last Sunday's 1-1 draw with Manchester City.
And Carragher, who has played alongside Lucas for the past four years, believes that Liverpool will struggle to fill the void left by the midfielder's long-term lay-off - claiming his influence on the team is on a par with top-scorer Suarez.
"For the last 18 months, in my opinion, he has been our best player," Carragher said. "Luis Suarez has come in and done great things for the club but Lucas has been his equal in many ways.
"He has been as good as anyone in the team this season and there is no question he will be a big miss."
Lucas struggled to assert himself in his first few seasons at Anfield, but has transformed into an integral part of Liverpool's first XI, and Carragher believes his team-mate's strength of character has been key.
"I have been there in terms of receiving criticism," Carragher said. "High standards are expected when you play for one of the big clubs and there are plenty examples of players who have gone missing after realising the demands on them.
"But you can tell Lucas is a top player as he never lets that bother him. He has just got on with it and plays in nearly every game. If he has a little knock, he will always try and carry on, doing his best for us. There are lots of different characters but you can't fault Lucas."