Modric claims Cattermole's studs-first tackle in the 1-1 Barclays Premier League draw at White Hart Lane could easily have broken his leg.
Modric, who stayed down for some time following the tackle, left no doubt where he stood, saying: "Players who tackle like that need to think before making a tackle because they can ruin careers of friends and professionals. They just need to think about it."
He added: "He should have been sent off. I can't show you now but there is a big swelling on my knee and he should have got a red card but the referee decided differently."
Midfielder Cattermole was shown a yellow card for the 69th-minute incident, which sparked a brief melee between opposing players.
Spurs boss Harry Redknapp was adamant Cattermole should have been sent off for the third time this season, while opposite number Steve Bruce was equally convinced the challenge was fair.
Modric said: "When you see tackles like that, it is a little upsetting, and if they are not punished properly then even more so.
"For now, it is a little bit sore but I hope it will settle down.
"I jumped and if I stayed with my legs on the floor it would have been even worse, but I got out of the way at the last second.
"Maybe if I stayed on the floor I would have broken my leg but I jumped and that has probably saved me. Thank God everything finished well."
Source: PA
Source: PA