That time it was the return of Wayne Rooney that supposedly sparked the violence, but after Gary Neville's badge-kissing incident last month there could be trouble again on Saturday.
"There is a different dynamic for this game from last year," said Chief Ch Supt Andy Ward. "There will be 6,000 travelling fans coming from Manchester, which is double the normal number of around 3,000.
"I can't give exact numbers but we will have more officers on duty than for a normal match.
"We've learned a lot of lessons from last year and also from other games, including the recent Millwall match.
"It's very early stages but at the moment we do not have any specific intelligence about possible problems, unlike the Millwall game."
