Atlanta Braves outfielders Justin Upton, left, and his brother B.J. Upton, right, listen to a coach during a spring training baseball workout in Kissimmee, Fla., in this Feb. 20, 2013, file photo.

ATLANTA - B.J. and Justin Upton took side-by-side lockers during their first spring training together. Even so, they rarely came across as anything more than just teammates.

Sure, there was plenty of good-natured ribbing. Other times, they chatted quietly. Mostly, they stuck to their own space -- one gently swaying to the tunes in his headphones, the other sipping on a drink and fumbling through some papers.

You know, like any other teammates in the Atlanta Braves clubhouse.

"These guys spend so much time together during the course of the year, it's almost like everybody's a brother," said Braves manager Fredi Gonzalez. "I haven't treated them any different. I haven't even thought about it. The only time it comes up is when somebody asks me, 'How do you handle the brothers?' I'm like, 'Uhh, I don't know."'

Baseball has long been a family game, but the Uptons coming together in the Atlanta outfield -- B.J. starts in center, Justin beside him in left -- puts them in a rather exclusive club: brothers-slash-teammates.

When the Uptons trot out together for the Braves opener Monday night, they'll be the 101st set of brothers to play on the same team, according to the website Baseball Almanac.

"An opportunity like this doesn't come along very often," said Sandy Alomar Jr., who got a chance to play with his Hall of Fame brother, Roberto, on three teams. "There's 750 players in the big leagues, on a planet with 6 billion people. You've got to be very, very grateful. ... That's like a needle in a haystack."

Even rarer, the Uptons are comparable in ability -- two players with power, speed and solid defensive credentials, two players the Braves are counting on heavily to lead the team to another playoff berth after the retirement of longtime slugger Chipper Jones.

This isn't a brother duo like, say, Cal and Billy Ripken, who were teammates for seven seasons with the Baltimore Orioles but never got confused with the other. Cal Jr. was the iron man, the Hall of Famer who played more consecutive games than anyone in baseball and a heavy-duty hitter. Billy was a light-hitting middle infielder who retired with a .247 average and 20 career homers.

Cal Ripken said the Uptons will push each other, which could make them even better players than they were with their former teams. And, remember, they weren't too shabby before they got to Atlanta: 25-year-old Justin finished fourth in the NL MVP voting with Arizona in 2011; 28-year-old B.J. had 28 homers and 31 stolen bases for Tampa Bay last season.

"There could be some interteam competition with them, which I think will be really healthy," Ripken said. "The game gets so long with 162 games, a lot of times you have to find different forms of motivation because there are so many ups and downs.

"It's not going to be about who can one-up each other. But because they know each other so well, I think that will help some of those days when it is difficult to show up. I love the dynamic, and I'm very curious and very interested to watch the Braves more because of the brothers."

Of course, if one brother performs up to expectations and the other struggles, it could heighten the pressure.

There's already a bit of an unusual dynamic when brothers double as teammates.

"In situations where you have to confront your brother, where maybe he's out of line and I have to confront him or I'm out of line and he has to confront me, those are challenging situations," recalled Alomar, who now coaches with the Cleveland Indians.

The key, he said, is to make sure any bad feelings don't carry beyond the ballpark. That's can be tough because all siblings bicker at times, and anyone who's got a brother or sister knows that often it's harder to soothe hurt feelings when you're family.

"With a brother, it lingers a little longer," Alomar conceded. "But you can get over it."

Out of the already small sampling of brothers who have played together, there are only 22 sets who spent as many as three seasons with the same team. The Uptons appear likely to join that exclusive group. B.J. was signed by the Braves as a free agent to a five-year, $75.25 million contract. Justin, who was acquired from Arizona, is under contract for three more seasons.

"It's been a cool experience so far," B.J. said. "It's going to get a lot better during the season."

The pairing almost didn't happen. The Diamondbacks actually worked out a trade that would've sent Justin to the Mariners but he vetoed the deal, taking advantage of a provision in his contract that allowed him to nix a short list of cities, Seattle included.

At that point, it was clear the younger Upton wouldn't be staying in Arizona. The Braves, who already had signed B.J., jumped back into the mix and pulled off a blockbuster seven-player trade with a package of players that included one-time All-Star Martin Prado.

The Uptons were ecstatic about the chance to play together for the first time since high school, when B.J. was a senior and Justin was a freshman.

"We get to spend more time together and we get to play baseball," Justin said. "At the field, we're teammates. Obviously, he's still my brother. But in here we're teammates. We all have the same goal in this clubhouse. Now away from the field, we'll be like brothers."

If you disregard the names on their uniforms and the similarities in their faces, it would be easy to forget the Uptons are brothers. B.J. is about an inch taller at 6-foot-3 and checks in at around 185 pounds. He looks almost skinny next to his burly brother, who outweighs B.J. by about 20 pounds.

During spring training, at least, they both seemed to thrive on the chance to be teammates. B.J. batted .347 with two homers and 10 RBIs. Justin hit .288 with a team-leading 19 RBIs and six homers, including a couple of prodigious drives -- one of which cleared the grass berm in left field at the Braves' Disney World complex, the longest homer anyone could remember at that stadium.

"If I can stay healthy, I think I can be a force in this lineup," said Justin, who is coming off a subpar season in which he was bothered by a thumb injury.

Hank Aaron was excited about the deals that landed both Upton brothers, and he believes the adjustment to being teammates will be much easier than it was for the Hammer and his younger brother, Tommie.

Aaron already was one of baseball's greatest players when Tommie joined the Braves in 1962. The younger sibling played 141 games his rookie season but was never more than a part-time player after that. Shuttling between the minors and the majors, Tommie spent parts of seven seasons with his famous big brother, always facing unattainable expectations because of the name on his jersey.

"I was a little despondent because I didn't think my brother played as much as he should have," Hank Aaron told a group of reporters during a stop at spring training last month. "There was a lot of pressure on him to continue doing what I was doing, and it wasn't like that. It wasn't that easy."

The Aarons hold the record for most homers by brothers, but Hank, of course, accounted for 755 of those. Tommie, who died from leukemia when he was only 45, finished his career with 13 homers.

The Braves are hopeful the Uptons will follow the lead of another set of brothers, Paul and Lloyd Waner. Known as "Big Poison" and "Little Poison," they played together in the Pittsburgh Pirates outfield for 14 seasons beginning in 1927. They combined for 5,611 hits -- more than any other siblings -- and both wound up in the Hall of Fame.

While no one is predicting Cooperstown just yet for either of the Uptons, they certainly seem more in line with the Waners than the Aarons.

"Both these kids have had success in the big leagues, so that should help quite a bit," Aaron said. "One's not overshadowing the other. I think they can help each other, no question about it."