The Monaco boss says the Colombian is progressing well in his recovery from a knee injury.
The 28-year-old has been out of action since January after sustaining knee ligament damage and warned last month that he would not rush his comeback simply to force his way into Jose Pekerman's squad for Brazil.
Ranieri, however, says the former Atletico Madrid striker has been progressing well in his rehabilitation and believes he has an excellent chance of making the tournament should his recovery continue unabated.
"Falcao is incredible. He is sharper than before. He's running and it's going well. If he continues like this, I think he'll be able to play for Colombia at the World Cup, but unfortunately not for us before the end of the season," he told Canal Plus.