The Leicester man pleaded guilty to the offence, committed against former England wing Steve Hanley, when he appeared before an RFU disciplinary panel in Coventry.
"Ellis was charged with foul play by the independent citing officer after the Powergen Cup sixth round tie against Sale Sharks at Welford Road on November 15," read an RFU statement.
"He pleaded guilty to the offence, against Sale's Steve Hanley, when he appeared before a Rugby Football Union (RFU) disciplinary panel. Ellis will be free to resume playing again on February 3, 2004.
"The disciplinary panel was Chaired by Richard Moon (Cambridge University) and also included Peter Baines (Hertfordshire) and Dr Matthew Lohn (co-opted member)."
Tigers Director of Rugby Dean Richards said afterwards of the decision: "Harry pleaded guilty to this offence, and the panel stated that they believed there was no intent on his behalf to injure any other player, but they found that his actions were reckless.
"We have 24 hours to lodge any possible appeal against the sentence, and will consider the position tomorrow [Tuesday]."