The Leicester centre is in hot water following his punch on Chris Ashton during Saturday's Aviva Premiership play-off.
Tuilagi looks set to be cited on Tuesday and face a Rugby Football Union disciplinary hearing later this week.
Although the 19-year-old escaped with a yellow card for hitting Northampton ace Ashton, he can now expect to land a ban that will probably sideline him for the Premiership final against Saracens on May 28 and possibly next month's Churchill Cup campaign with England Saxons.
And ex-Northampton and Bath player Sleightholme has little sympathy with one of English rugby's brightest midfield prospects.
"There is no chance of him stepping into an England jersey with petulance like that," said Sleightholme, writing in the Northampton Chronicle and Echo.
"He has a lot to learn, and you would have thought that he might have had some time for contemplation with 10 minutes in the 'cooler,' but there were several incidents in the second-half when he sailed very close to the wind, along with his brother Alesana.
"They clearly had targeted Ashton, and Tuilagi the elder was lucky not get a reprimand for a high shot on the England flyer.
"I am sure that the citing officer and the disciplinary panel will make an example of Manu, and the outside chance that he had of being in England's World Cup squad were extinguished in a blow.
"I was never one of those calling for his immediate promotion, as defensively, he has a lot to learn.
"But he also proved on Saturday that he has to grow up a fair bit before he can be trusted in the much more exposing environment of Test match rugby."
Saturday's game, won 11-3 by Leicester, was watched from the stands by England manager Martin Johnson, red rose forwards coach John Wells and scrum specialist Graham Rowntree.
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