It was announced by MLB that Yankees manager Joe Girardi, in control of the reins for the AL, added Oakland's Andrew Bailey and Detroit's Justin Verlander, a pair of heat-dispensing right-handers, to replace Cahill and Weaver.
The National League, meanwhile, acquired a Southern California feel with its two additions: Dodgers shortstop Rafael Furcal, replacing the Mets' injured Jose Reyes, and southpaw reliever Hong-Chih Kuo, filling the roster spot vacated by injured Braves right fielder Jason Heyward.
Weaver, who was selected as a replacement for Sabathia, the Yankees' ace lefty, is unable to pitch in the game on his home field because of the new regulations in force regarding pitchers.
Those who start games on Sunday cannot throw a pitch on Tuesday, meaning Sabathia, Weaver and Cahill -- Bailey's teammate with the Athletics -- were ineligible to compete as soon as they launched their first deliveries on Sunday.
Weaver, Cahill and Sabathia are recognized as All-Stars with full honors, attending the festivities and introduced before the All-Star Game.
Verlander owns an 11-5 record with a 3.82 ERA and 110 strikeouts in 115 1/3 innings pitched.
Bailey, the 2009 AL Rookie of the Year, is in the midst of another brilliant season as the Athletics' closer en route to his second All-Star Game. He claimed his 18th save on Sunday against the Angels and carries a 1.70 ERA in 37 innings.
"I had heard if Cahill threw a pitch, Weaver was going to take his spot, and if Weaver threw a pitch, I was going to take his spot," Bailey said. "So I was down there cheering each and every first pitch of each inning. Guys in the bullpen were giving me high fives, and I've never seen so many cheers in the bullpen after the second pitch of the game. It was exciting.
"Trevor obviously deserves to go down there and represent our team, and I'm happy I can accompany him down there. It's a tribute to how hard we work and our team, and it's nice to be able to go down there representing the A's."
Bailey gives the A's multiple All-Star representatives for the first time since 2004, when starters Mark Mulder and Tim Hudson joined forces. Bailey is the first A's closer to make the team in consecutive seasons since Dennis Eckersley from 1991-92.
Bailey didn't' get the call to pitch in last year's All-Star Game.
"If I get an opportunity, obviously I'll take full advantage of it," he said. "The representing pitchers probably have a lot more time than me, so if I happen to get in there, it'd be awesome. But it's all about having fun, so either way, it will be a good time. It's good. Trevor and Weaver and those guys can hang out and enjoy the moment, and I'll be nervous as heck in the bullpen."
Verlander, an All-Star for the third time, can help calm him down.
"Absolutely," Verlander said when asked about the excitement created with his selection to the team. "The All-Star Game is the All-Star Game, no matter how you get there.
"Going as a reserve is not the first choice I would have. But being able to go and represent the Tigers and this city means a lot."
He'll join teammates Miguel Cabrera, the starting first baseman, and reliever Jose Valverde on the AL roster.
Verlander said it will be "exciting to watch the [State Farm] Home Run Derby and watch Miggy put on a show like he does every day here for us at batting practice."
Kuo becomes the first Taiwan native to make a Major All-Star team, and it comes in the aftermath of his recovery from two Tommy John surgeries.
"It's a dream come true for me," Kuo said.
NL manager Charlie Manuel of the Phillies initially extended the offer to veteran Braves closer Billy Wagner, who turned down the opportunity in order to rest a sore ankle. The Brewers' Corey Hart will start in Heyward's place.
Kuo and Furcal bring the Dodgers' representation in Anaheim to four with starting outfielder Andre Ethier and closer Jonathan Broxton.
"It was great -- he was excited, he is excited I should say," said Dodgers manager Joe Torre, who will be on the National League's bench as one of Manuel's coaches. "And between the time we met yesterday and now, the two guys we talked about [Kuo and Furcal] are on the All-Star team, and the real great news is they're both tickled to think about it."
Kuo took a 1.03 ERA into Sunday's game, leading all NL relievers with at least 25 innings. He's 3-1 with two saves and a strikeout-to-walk ratio close to 5-to-1 in 25 appearances. Opponents are hitting .129 off him with runners on base.
Furcal, 32, was disappointed when he initially was passed over for the NL's roster. He missed a month because of hamstring injury, then a little more time to visit his father in his final days.
His batting average of .333 would lead the NL if he had enough plate appearances to qualify. He even set the Los Angeles record for scoring a run in 12 consecutive games, last done by Gil Hodges in 1953 when the Dodgers belonged to Brooklyn. Furcal had six home runs, including four in his last 11 games, 35 RBIs, 50 runs scored and 14 stolen bases.
Weaver, joining teammate Torii Hunter on the AL's All-Star roster, is in line for a $50,000 contract bonus. He's happy to cancel a planned trip to Napa, Calif., during the break to take a bow when the teams are announced before the game.
"It's a tremendous honor," said Weaver, whose loss to the A's left him at 8-5 with a 3.20 ERA and Major League-high 137 strikeouts. "You think of when you were 9 years old, and you think of all the great guys that have come up through the league. To be named an All-Star is kind of surreal -- it hasn't really hit home.
"It's going to be a trip to be surrounded by all those guys you've looked up to for so many years and to be able to go up to them and shake their hands is going to be great. Some people go their whole career without getting an All-Star Game. To be able to line up on that line and tip your cap to the people that supported you over the past four or five years is going to give me goose bumps, I'm sure. To have my friends and family be able to go and check it out is great. I'm very humbled."
Hunter was thrilled Weaver was recognized.
"That's good we got two guys there to represent us," Hunter said. "We're hosting the All-Star Game. And Weaver, he's deserving."
The 81st Major League Baseball All-Star Game will be televised nationally by FOX Sports, in Canada by Rogers Sportsnet and Sportsnet HD and Le Reseau des Sports, and around the world by Major League Baseball International, with pregame ceremonies beginning at 8 p.m. (EDT)/5:00 p.m. (PDT). ESPN Radio will provide exclusive national radio coverage. MLB Network, MLB.com and Sirius XM also will provide comprehensive All-Star Game coverage.
Lyle Spencer is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.