''Maybe after practice,'' he cracked, chuckling while sitting at his locker before the San Francisco Giants hit the field for their first full-squad workout.
A few hours later after seeing Bumgarner in person, he had changed his tune completely.
No way, not happening.
Shortstop Brandon Crawford could have told his new teammate that much. Crawford had already planned to advise him against taking on the 6-foot-5, 235-pound reigning World Series MVP.
''That would probably be my advice, don't do it,'' Crawford said. ''If he is going to do it, I'd go for the hair if I was him. That's his weak spot, that's his Achilles' heel.''
Center fielder Angel Pagan put his money on his outfield mate, even if at 5-9 and 180 pounds, Aoki has a serious size disadvantage.
''That's my way to win against Bumgarner,'' Aoki said.
Hunter Pence won't try to talk Aoki out of a showdown, offering a, ''Have fun, good luck.''
All good-natured wrestling talk aside, the Giants are thrilled with how their outfield is shaping up considering Pagan is healthy after the back surgery that derailed his 2014 season, the speedy Aoki is ready to be the regular left fielder, and Pence, well, he's just the durable, do-everything Pence who plays every day in right. Gregor Blanco, who could be a starter on many teams, will begin as the fourth outfielder.
''We have a lot of options, a lot of really good bats and really good defenders,'' Pence said. ''That's a really good addition (Aoki).''
The 33-year-old Aoki signed a $4.7 million, one-year contract in January after losing to the Giants in the World Series last fall with Kansas City. He could become the leadoff hitter depending on how Pagan comes along this spring.
Aoki batted .285 with a home run, six triples, 22 doubles and 43 RBIs over 132 games in his lone season with the Royals after two in Milwaukee. He also stole 17 bases.
Manager Bruce Bochy told Aoki he's expecting 30 home runs this season, to which the good-natured outfielder promised to hit 24.
Pagan is ready to put up his own big numbers as he looks to stay in the lineup now that his back is pain-free. Last year, he tried to play through despite the challenges of even getting out of bed in the morning.
''If you see a picture of my body, it looked like a Z when I got up,'' he said. ''My mornings were miserable.''
Pagan played in only 96 games last season and 71 in 2013 because of injuries. He looks back and is happy he chose to have surgery, for his career as well as his quality of life beyond baseball.
''I had to think of the future,'' he said. ''I'm so glad I got it done and out of the way.''
He recently told Bochy he's planning for 160 in 2015, the third season of his $40 million, four-year contract.
''He really feels great, he's very upbeat,'' Bochy said. ''When you feel as good as he does, you're pumped about getting it going and starting a new season. It's a new slate for everybody, including him. You can see the smile on his face.''
Bochy plans to experiment with some different batting orders early in Cactus League play beginning next week before settling into a more regular lineup in mid-March.
As usual, Pence joined Bochy in addressing the team before Tuesday's workout at Scottsdale Stadium.
The every-other-year Giants - they've won championships in 2010, '12 and last year - want to capitalize on the momentum from last season to keep on a roll given the fleeting opportunities in professional sports.
''This is a big day,'' Bochy said. ''We had a great year last year. ... We'll still enjoy and savor those memories but at the same time it's time for us to get ready. Your clock on success is as good as your last game. In this game, your time's limited. It's been great to have this type of success that we've had. That window, it's not always going to be there. You've got to seize that moment.''
Aoki appreciated Pence's pep talk, which he described as ''full of passion.''
''We're playing for a championship,'' he said through interpreter Kosuke Inaji, who has worked with Aoki throughout his major league career. ''I had a lot of fun.''