Amazing Race All-Stars

Eleven teams are set to take to the starting line again on The Amazing Race All-Stars (Sunday, 8/7c, CBS) — key word being "set."

For the first time, one team will be prohibited from going on the Race. "After a thorough examination, our doctor determined that one team is not capable of going because of a medical concern that we had about one team member," host Phil Keoghan tells TVGuide.com. "The emotion at the start of this Race is unlike any that we've ever had before. I have to break the news to everyone else. It's obviously devastating and affects not only that team and the other teams, who realize that suddenly there's this major change. This is absolutely the most dramatic thing that's ever happened. It's gut-wrenching. It broadsided us."

Photos: Meet The Amazing Race All-Stars cast

Nevertheless, 11 teams will still take off around the world — "you'll have to see what we decided to do," Keoghan teases — for the second and, in three cases, third times. This is the show's third all-stars outing, coming three years after the second Unfinished Business-themed one. "I think there are a lot of fans who really like all-stars," Keoghan says. "We're constantly getting hit with ideas of various combinations. It seemed timely to do another one now because there are so many teams that have come so close and there are so many great stories within those teams. There isn't a team up there that doesn't have a really great story. We listened to the fans in terms of who to come back. That doesn't mean all fans will agree with all the choices. I'm just saying those teams fans are talking about the most."

So how did the show come to pick this roster? Keoghan breaks it down below.

Leo and JamalSeason 23 — 4th place
Last we saw them: The Afghanimals/cousins missed out on a final three spot when Leo messed up the button configuration on a robot.
Why they deserve to be on All-Stars: The Afghanimals were widely perceived to be sneaky master manipulators by most of the Season 23 cast, a label that irked them but that they also relished. "They have that very competitive, loud streak," Keoghan says. "We saw how the teams last season reacted to them. How will a new group of teams regard them? They ride that line of being entertaining and annoying in some people's eyes. The interesting thing is, they did back-to-back seasons, so will they be tired as well?"

Brendon and RachelSeason 20 — 3rd place
Last we saw them: Crying and arguing with nemeses Vanessa and Ralph, and each other.
Why they deserve to be on All-Stars: Arguably the most divisive team this season (and maybe ever), the Big Brother alums were an "obvious" choice for All-Stars, Keoghan says. "Their fans are incredibly loyal and there are some people who just cannot stand them," he says. "Rachel is such a larger-than-life reality character with her bickering and the two of them going at each other. You turn on the camera and you're guaranteed something interesting. How could you not have them back? Even people who don't like them as a team know that just by putting them in the mix with teams that they like know they're going to get content. That's the key of the show. We can't just pick the most popular based on how nice they are. We also have to put in teams that are going to stir things up."

Jennifer and CarolineSeason 22 — 4th place
Last we saw them: The country singers rode an alliance and near-showmance with eventual winners Bates and Anthony to a fourth-place finish.
Why they deserve to be on All-Stars: To prove they're not a fluke. "I think they surprised everybody, including themselves with fourth place last time. They are out to have a good time," Keoghan says. "They worked with the hockey players last time. I know some fans don't think they would've gotten that far without them. What can they do this time? Will they work with another team?"

Jet and CordSeason 16 — 2nd place; Season 18 — 6th place
Last we saw them: The Harlem Globetrotters U-Turned them in Switzerland on Unfinished Business.
Why they deserve to be on All-Stars: One of the three-timers, the fan favorite cowboys were another irresistible pick. "There's never been a team that has been asked about more than the cowboys," Keoghan says. "People just love them. They're delightful, they're competitive and they're great Racers. That combination is rare." As for them getting yet another chance, Keoghan says there's no hard and fast rule that says teams can't be on more than twice. "At the end of the day, regardless of whether they're coming back a second or third time, that lineup is based on fan feedback and the strength of their story."

Exclusive: Brendon and Rachel "so excited" to return for Amazing Race All-Stars

Dave and ConnorSeason 22 — 8th place
Last we saw them: The father-son cancer survivors withdrew after Dave tore his Achilles' tendon, but not before winning a leg with the help of an Express Pass.
Why they deserve to be on All-Stars: How could you not give a team like that a second shot? "Dave was literally running the race for so long on one leg. People loved that story and wanted them to come back and race again," Keoghan says. "They had really horrible luck last time. Who knows how well they could've done had that not happened. They were clearly a strong team even with Dave on one leg."

Flight Time and Big EasySeason 15 — 4th place; Season 18 — 2nd place
Last we saw them: The Globetrotters couldn't figure out a table setting in the final Season 18 task and had to copy eventual winners Kisha and Jen's.
Why they deserve to be on All-Stars: "They're just a lot of fun. You need that," Keoghan says. "At one point, they just get down and start dancing. They are absolutely focused on having a good time. They love each other like brothers. They add the fun and humor and comedy and are not into the drama like some other teams."

Jessica and John, Season 22 — 9th place
Last we saw them:
 They became the first team ever to be eliminated while holding an Express Pass — and John declared he had "no regrets," cuing up Keoghan's famous "oy vey" eye roll.
Why they deserve to be on All-Stars: Redemption, duh. "That 'oy vey' moment has been haunting them," Keoghan says. "To John's credit, he's being very graceful about admitting he made a mistake. But before that happened, they were a very strong team that some people picked to win it all."

Margie and LukeSeason 14 — 3rd place; Season 18 — 8th place
Last we saw them:
 They were eliminated after Luke spent hours drinking tea to find a clue.
Why they deserve to be on All-Stars: Like Brendon and Rachel, the mother-son duo —he, the show's first and only deaf racer — are a love 'em or hate 'em tandem. "They're quite controversial. I know fans who are inspired by them and fans who cannot stand them and find Luke whiny and irritating," Keoghan says. "They're also very ruthless. You saw how they U-Turned Amanda and Kris [in Season 14]. You need characters like them."

Natalie and NadiyaSeason 21 — 4th place
Last we saw them: The self-professed twinnies got lost en route to the Pit Stop, but are most remembered for keeping James and Abba's money that they found on the floor.
 Why they deserve to be on All-Stars: They're another divisive team. "The twinnies can rub a lot of people the wrong way," Keoghan says. "They are loud and can be quite inappropriate with their boisterous behavior. Can't you just picture them going up against Rachel? I'm not saying that's going to happen, but the possibility of that is what you want."

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Joey and MeghanSeason 22 — 5th place
Last we saw them:
 They failed to check for earlier flights and got the boot after going head-to-head with Mona and Beth for the last spot in the final four.
Why they deserve to be on All-Stars: They're the underdogs. The YouTube hosts were middle-of-the-pack racers, scoring a second-place finish just once, a week before their elimination. They also have the dubious honor of being the first team to be U-Turned twice in a season. "Joey and Meghan are fun, young team, and I think they're quietly threatening," Keoghan says. "They weren't the strongest team last time, but they're definitely that team that could play spoiler."

Bopper and Mark, Season 20 — 5th place
Last we saw them:
 Despite completing a Fast Forward, the BFFs got eliminated after falling so far behind the previous leg when Mark struggled with a Bollywood dance.
Why they deserve to be on All-Stars: Their aw-shucks demeanor, charm and enthusiasm is only rivaled by the cowboys. "I don't know anyone who doesn't like them," Keoghan says. "They're not the best racers ever, but the thing people respond to the most is their friendship and bond. Everyone was begging them to come back after they were eliminated." 

The Amazing Race All-Stars premieres Sunday at 8/7c on CBS.

(Full disclosure: TVGuide.com is owned by CBS.)