Voting is under way as fans help decide the prestigious Roberto Clemente Award presented by Chevrolet, as MLB commemorates the extraordinary legacy of No. 21 with its 12th annual Roberto Clemente Day on Tuesday and then ultimately announces a recipient during the 109th World Series.

Roberto Clemente Day was established by MLB to honor Clemente's legacy and to officially recognize 30 nominees, one for each club. The annual award, won last year by Dodgers ace Clayton Kershaw, goes to a player who best represents the game of baseball through positive contributions on and off the field, including sportsmanship and community involvement.

The Roberto Clemente Award pays tribute to the namesake's achievements and character by recognizing current players who truly understand the value of helping others. Clemente, a 15-time All-Star and Hall of Famer, died in a plane crash on New Year's Eve 1972 while attempting to deliver supplies to earthquake victims in Nicaragua.

American League nominees are Adam Jones of the Orioles, Craig Breslow of the Red Sox, Hector Santiago of the White Sox, Justin Masterson of the Indians, Miguel Cabrera of the Tigers, Jose Altuve of the Astros, Billy Butler of the Royals, Jered Weaver of the Angels, Justin Morneau of the Twins, David Robertson of the Yankees, Sean Doolittle of the A's, Raul Ibanez of the Mariners, David Price of the Rays, J.P. Arencibia of the Blue Jays and Ian Kinsler of the Rangers.

National League nominees are Aaron Hill of the D-backs, Tim Hudson of the Braves, Anthony Rizzo of the Cubs, Bronson Arroyo of the Reds, Todd Helton of the Rockies, Adrian Gonzalez of the Dodgers, Logan Morrison of the Marlins, Jonathan Lucroy of the Brewers, David Wright of the Mets, Chase Utley of the Phillies, Andrew McCutchen of the Pirates, Carlos Beltran of the Cardinals, Mark Kotsay of the Padres, Barry Zito of the Giants and Ryan Zimmerman of the Nationals.

"It's an honor to be nominated for the Roberto Clemente Award," said Masterson. "So many people have been nominated in the past have done such great things. To whom much is given, much is required, and I try to live by that."

"Look at Roberto Clemente, at what he did," McCutchen said. "I don't want people to know me because I played baseball. I want people to know me for other things I did outside a baseball field. Yeah, Clemente was a great baseball player, but the things he did off the field said more about him. That's the person that I admire, and that's how I want to be."

The finalist selection process is nothing new for Hudson, who has garnered his seventh nomination in the past eight years, but he has yet to win the overall MLB award. Hudson was also nominated four times (2001-2004) while playing for the A's.

"Giving back and helping children is something that my wife, Kim, and I have enjoyed doing throughout my big league career," Hudson said previously. "We know how fortunate we are, and the importance of giving back."

"Any time you get mentioned for anything about the Roberto Clemente Award is a tremendous honor," said Hall of Famer Al Kaline, who received the honor in 1973. "Certainly after they renamed it and I was the first recipient, I was thrilled and honored."

Willie Mays won the first of these honors in 1971, when it was known as the Commissioner's Award, to recognize community service around the game. He is one of 14 Hall of Famers on the distinguished list of recipients. After 1972, the award was dedicated in Clemente's name.

Helton announced over the weekend that he is retiring at the end of this season, following a 17-year career spent entirely with Colorado. Morneau, meanwhile, is the only nominee not currently with the club he represents, as he earned the Twins honor but now plays for the Pirates.

The winner of the fan vote will receive one vote, with the rest cast by a selection panel that includes Commissioner Bud Selig; MLB Goodwill Ambassador Vera Clemente, Roberto's widow; FOX broadcasters Joe Buck and Tim McCarver; Hall of Fame Broadcaster and the "Spanish Voice of the Dodgers" Jaime Jarrin; Hall of Famer and TBS analyst Dennis Eckersley; TBS analyst Buck Martinez; MLB Network analysts and former Clemente Award winners Al Leiter and Harold Reynolds; Hall of Famer, ESPN analyst and former Roberto Clemente Award winner Barry Larkin; ESPN analyst and former Roberto Clemente Award winner Rick Sutcliffe; MLB.com senior correspondent Hal Bodley; and Chevrolet national promotions manager Mike Weidman.

Clubs playing at home on Tuesday will recognize their local nominees as part of Roberto Clemente Day ceremonies, while visiting clubs will honor their nominees at a home game before the season ends. As part of the league-wide celebration, the Roberto Clemente Day logo will appear on bases and the official dugout lineup cards.

As part of the balloting to help decide the award, participating fans will be automatically registered for a chance to win a trip to this year's World Series.