The 27-year-old found himself in hot water with the Rugby Football Union disciplinary committee after he struck Sale's TJ Ioane with his shoulder in Harlequins' 30-29 defeat against the Sharks.
Marler's previous disciplinary record meant he had initially been handed a seven-week ban, but after pleading guilty to the offence the suspension was reduced to six weeks. His conduct since the incident was also taken into account.
Even so, it means Marler will miss England's opening match in Italy on Sunday, February 4 and the home game against Wales six days later, but he will be back available for the away fixture against Scotland on Saturday, February 24.
Meanwhile, Ioane was banned for two weeks after pleading guilty to striking Marler with his arm earlier in the same game.