Tuilagi was banned for five weeks after landing three punches on England wing Chris Ashton during the Aviva Premiership semi-final victory over Northampton last Saturday.
That cost the 20-year-old his place in next week's final against Saracens and ruled out any involvement for Tuilagi in the Churchill Cup with the England Saxons, but Cockerill hopes senior national team manager Martin Johnson can see past the incident.
Cockerill told The Observer: "What Manu did was unacceptable. He has paid a harsh penalty, missing the grand final, and it could affect his World Cup chances with England.
"I think he still has a chance of being in the wider World Cup training squad. The England manager got into enough scrapes as a player to understand how it works. He sometimes reacted poorly in highly-charged environments.
"These things happen and I am sure Martin would look at it in the same way. Manu is good enough to play for England.
"He reacted, in a big and important game, very poorly to something that happened to him. He is a young man who is very physical but not dirty. He should not have done what he did and he knows that.
"I played the game and I did things I should not have. I know what he did is indefensible, but I want to support Manu because he is a unique talent and he is not that sort of player or person."
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