Commissioner Bud Selig conducts a news conference announcing baseball’s new collective bargaining agreement. (Patrick McDermott/GETTY IMAGES)

Major League Baseball and the MLB Players Association announced a new collective bargaining agreement, ensuring labor peace between the sides through 2016 and guaranteeing 21 consecutive years without a work stoppage since the 1994 strike, the longest uninterrupted stretch since the formation of the modern Players Association in 1966.

Baseball’s sustained labor peace comes at a moment when the NBA is mired in a potentially season-killing lockout, the NFL recently endured a messy work stoppage and the NHL is still rebounding from the canceled 2004-05 season. The unprecedented harmony, not coincidentally, has followed unprecedented financial growth. Baseball’s revenues, even in a spiraling economy, have risen each year since 2003, surging from less than $4 billion in 2003 to more than $7 billion this year.

Baseball’s owners and players have historically held more animosity in regard to labor issues than any other sport. But their shared prosperity under Commissioner Bud Selig and the league’s hugely lucrative Advanced Media arm has motivated each side to work together.

The sides have reached only a memorandum of understanding and each side must still ratify the deal. But all considerable hurdles have been cleared.

“I believe this five-year agreement will continue the remarkable popularity and surge that baseball has been on,” Selig said in a news conference, with MLBPA director Michael Weiner sitting to his immediate left. “Nobody back in the ’70s, ’80 or early ’90s would ever have believed we would have 21 years of labor peace. . . . This is really a proud day for us.”

The new deal contains numerous changes, some noticeable primarily behind the scenes and some that will change the face of the sport, some radical and some subtle.

●The deal hinged largely on an agreement on compensation for draft choices. MLB will institute a luxury tax on teams that cross a specific threshold while spending on signing bonuses in the draft. The total will range from $4.5 million to $11.5 million, depending on draft position and number of picks. The tax will be applied based on total money spent, not per player.

Teams may still hand out big bonuses, but severe penalties will provide a huge deterrent. If teams spend 5 percent over their allotted “slot” amount, they must pay a 75 percent tax. Teams that go over slot by 5 to 10 percent must pay a 75 percent tax and will lose a first-round pick. Teams that go over slot by 10 to 15 percent must pay a 100 percent tax and lose a first- and second-round pick. Teams that spend more than slot by 15 percent or more must pay a 100 percent tax and lose two first-round picks.

Also, teams may no longer sign drafted players to major league contracts, like the contracts the Washington Nationals have given to Stephen Strasburg, Bryce Harper, Anthony Rendon and Matt Purke in recent years.

Across the league, many worried the new rules will prevent baseball from attracting the best athletes in the country. Their thinking: The best athletes will play college football or college basketball without a significant payday from baseball, especially since college baseball teams do not provide full scholarships.

“I have no concerns about that,” Selig said. “I don’t believe that that’s a possibility. I believe the sport is on an upgrade at every level.”

Weiner pointed that the draft spending limits are only on aggregate spending, not individual spending, so the very best players will still receive lucrative deals.

“I don’t really worry about that,” Nationals scouting director Kris Kline said. “Those guys are so rare in our game. They are out there, but there are very few that are exceptional.”

●The sport also made significant changes to how teams can acquire international players. Teams will have a pool of money to spend on international talent, starting at $2.9 million next offseason. Teams in smaller markets that finish with the worst records receive bigger pools. Starting in 2014, teams will be allowed to trade as much as half of the money in their international pools.

●The league will implement blood testing for human growth hormone beginning this spring training, making baseball the first major U.S. professional sport to use the test. After spring training, players will be tested only if there is reasonable suspicion they are using. “It wasn’t that difficult” to pass, Weiner said. “We started to engage with the office of the commissioner in the spring of 2010 about HGH testing.”

●Starting in 2013, the Houston Astros will move from the National League Central to the American League West, leaving 15 teams in each league and instituting perpetual interleague play.

●An additional wild-card team will be added to each league, and Selig is “more than very hopeful” the two new playoff teams will be introduced for the 2012 season. Really, the only hold-up is MLB striking a deal with a network for television rights for the play-in games.

●Players, managers and coaches are now prohibited from carrying a tin or any other package of tobacco in their uniform at any time fans are allowed in the park. They are also prohibited from using tobacco during television interviews or at team-sponsored events.

Knock Tobacco Out Of The Park Coalition, a leading watchdog group for tobacco in baseball, supported the measure and pushed for the wholesale elimination of tobacco in ballparks.

“We continue to support a complete prohibited on tobacco use at games and on camera,” Coalition official Gregg Haifley said in a statement. “Still, this is significant progress. Baseball players have been using tobacco since the earliest days of the game. This agreement marks the first time that the league and the players have recognized it is time to break this unhealthy addiction.”

●The minimum major league salary will rise from $414,000 to $480,000 this year, an increase of 16 percent. The minimum salary will rise to $500,000 before the CBA expires.

●Previously, the CBA stated the agreement covered all players regardless of “race, color, religion or national origin.” The phrase “sexual orientation” will be added to those qualifiers in the new agreement.

●More players will be eligible for salary arbitration sooner. The top 22 percent of players who have between two and three years of service time will be eligible, rather than the previous 17 percent.