That's the only thing that seems different about Sweeney, though. From the moment he emerged from the A's clubhouse on Monday, the old Sweeney smile glowed with the old familiar warmth. No blarney here.
This was his first chance to see his old team. Sweeney spent 17 years in the Royals organization, signing in 1991 when he was 17 years old. He was their captain for the last six years, the face of the franchise for many Kansas Citians. Then, this winter it was time to move on.
The ties are still strong. When Sweeney came onto the field, the first guy he hugged was Billy Butler, the kid who took over Sweeney's designated hitter job. With that, the Sweeney hug-fest with his ex-teammates was on.
He wore No. 5 instead of his old 29, which already was assigned to pitcher Keith Foulke. So he chose 5 for his boyhood idol, the Angels' Brian Downing, and his manhood idol, George Brett.
"I always loved Brian Downing growing up, and then obviously becoming close with George the last decade or two in Kansas City," he said. "It's an honor to wear the number."
Sweeney went through pregame stretching with the A's, happily gabbing with No. 4, ex-Royals teammate Emil Brown, and No. 3, Eric Chavez.
He spotted Brett and two of his sons near the Royals dugout -- more hugs and handshakes. Justin Huber, who was hitting .400 with slim prospects of making the KC roster, got some encouraging words.
"I really miss the guys," Sweeney said. "I was talking to [Mark] Teahen today, and I said, 'How's it going over there?' He said, 'Oh, it's going great, but sometimes I'll look around and want to get some advice from you, and you're not around.'
"I looked him in the eye and I said, 'Well, you know what that means -- it's your time to lead.'"
The Royals kidded Sweeney about his A's white shoes.
"They make me faster," he said with a grin. "I've already got a bag [stolen base]."
Proud of his bilingual efforts, Sweeney spoke Spanish with Royals coach Luis Silverio. Moving into the batting cage, he peppered the left-field fence with line drives. Next was an autograph stop for kids at the rail, where he signed, among other things, his favorite book, the Bible.
With the red-rock Papago Buttes in the background, Sweeney took ground balls at first base followed by a quick lunch at a clubhouse table with Chavez and other teammates.
"Great group of guys -- seemed like it only took two or three days to fit in, and I'm just a part of the team now," Sweeney said. "Still no guarantees, but ..."
The A's still have not told Sweeney, who signed a Minor League contract, if he's made the club. Even after going 0-for-3 with a walk on Monday against the Royals, Sweeney was batting .333 (12-for-36) with 10 RBIs, three doubles and a home run.
Sweeney will go with the A's to Japan for their season-opening series on March 25-26 against the Red Sox. On the trip, each team will have a 28-man pool from which to pick its 25-man game roster.
"That's a step in the right direction," Sweeney said.
Sweeney has a clause in his contract that requires the A's to advise him by Wednesday if he'll be on the Opening Day roster.
"They're supposed to let me know by the 19th, which is the day we leave for Japan, but I think we're going to extend that a couple of days because they said they'd know something for sure by the 24th," he said.
Sweeney praised Royals general manager Dayton Moore for the way he handled his departure from KC.
"He was just honest. He said, 'We'd love to have you,' but he just said, 'There's no room. I don't want to bring you in in a position where you could only fail.' So once he closed the door, it was time to move on, and I respected him for that."
Looking trim and fit in his A's green and gold, Sweeney said he's had no recurrence of the back and knee problems that disrupted his last few seasons.
"This is the best I've felt in a long time -- 100 percent healthy, hungry and eager for an opportunity," he said.
After the 6-2 A's victory, Sweeney admitted to being a bit anxious against the Royals. He swung at the first pitch from Brian Bannister and bounced out.
"I was excited," he said. "It was great playing against my buddies."
Then he found some bubblegum for his son. Little Mike was all decked out in an Athletics jersey, too. The green seemed to be a Sweeney family fit.
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.