Just over four months after the ruckman was traded from the Sydney Swans to the GIANTS, he's set to line up opposite his former teammates when the clubs meet at Canberra's StarTrack Oval in the NAB Challenge.
The 27-year-old isn't a stranger to the situation, having played 21 games for Geelong before he moved to the Swans for the 2010 season.
He said he wasn't anticipating a negative reaction from his old Swans teammates.
"I'm not nervous at all. I'm actually looking forward to it," Mumford said on Wednesday before the GIANTS' light session.
"I had breakie with (Swans midfielder) Josh Kennedy during the week and we were stirring each other up, he reckons he's still going to be calling for me to hit it to him half the time, so I'll have to make sure I don't do that.
"I guess it's always a little bit awkward, that first probably three or four times you play against the old team but I'm not too nervous at all.
"There'll be a little bit of friendly banter here and there but I don't think there'll be anything too untoward."
Mumford signed a three-year deal with the GIANTS the day after two-time Hawthorn premiership forward Lance Franklin became a Swan.
He said he and fellow former Swan Jed Lamb would benefit from getting the match out of the way ahead of the round one clash between the crosstown rivals on March 15.
"There's no hard feelings there from anyone at the club," Mumford said.
"They know what happened and that's obviously a part of football.
"Everyone moves on and we go from there.
"Obviously you want to get it over and done with as quick as possible, that first one, and I guess the NAB Cup is probably not a bad format to do it."
Mumford said he would pass on his insight into how the Swans' midfield worked to his new teammates ahead of Thursday's game.
He also said the Giants were keen to blow off some steam in a fully competitive match after intra-clubs and match practice throughout the pre-season.
"You don't want to go flat out when you're playing against your teammates whereas now you're actually running into a few other bodies and it doesn't matter if you hurt them," he said.
"You'll probably see me flying around a little bit.
"We'll be going out there with the full intentions of having a real hard crack at the game.
"I know they'll be doing exactly the same so it should be good for the fans to watch."
