NEW YORK -- Blue Jays third baseman Josh Donaldson and Nationals outfielder Bryce Harper, the front-runners for the Most Valuable Player Awards in the American League and National League, respectively, have been named winners of the 2015 Hank Aaron Award.

MLB Commissioner Rob Manfred made the announcement before Game 4 of the World Series on Saturday night at Citi Field. The award recognizes the most outstanding offensive performer in each league.

• Previous Hank Aaron Award winners

"I congratulate Bryce Harper and Josh Donaldson on earning the 2015 Hank Aaron Awards, representing the best offensive seasons in the American and National Leagues," Manfred said. "At age 22, Bryce enjoyed great success, posting numbers that put him in the company of some of our game's all-time greats. Josh played a pivotal role in the Blue Jays' first playoff season in 22 years, contributing to one of the game's best lineups. Both players honored the enduring legacy of Hank Aaron with all-around excellence throughout the 2015 season."

"It is truly a joy and an honor that the award recognizing the top offensive performers in the game has my name on it," said Hank Aaron. "I want to congratulate Josh and Bryce on their outstanding seasons and extend my thanks to the Hall of Famers and fans who selected the winners."

• Nickname apropos for Donaldson's journey

The 29-year-old Donaldson batted .297 with a .371 on-base percentage and a .568 slugging percentage in 158 games. He ranked first among Major League leaders in runs scored (122), while leading the AL in RBIs (123) and extra-base hits (84). Donaldson also ranked second in slugging percentage, third in home runs (41) and fifth in hits (184).

"But my favorite stat, he had 20 game-winning RBIs," said Manfred. "That's some year."

Also, 27 of Donaldson's homers either tied the score or gave his club the lead.

Video: WS2015 Gm4: Donaldson, Harper win Hank Aaron Awards

Harper, who turned 23 on Oct. 16, had a dominant season, leading the Majors with a 1.109 OPS. He finished second in the NL with a career-best .330 average, adding 42 homers (tied for the NL lead), 99 RBIs and 118 runs scored (1st).

Harper became the first player in history with at least 42 homers, 124 walks and 118 runs scored at age 22 or younger. The 2012 NL Rookie of the Year Award winner became the sixth-youngest player in Major League history to reach the 40-homer plateau, joining Mel Ott (1929), Eddie Mathews ('53), Johnny Bench ('70), Joe DiMaggio ('37) and Juan Gonzalez ('92) as the only players under the age of 23 to do so.

"Bryce had an unbelievable year," Manfred said.

Harper was unable to attend, but he sent a video to express his appreciation.

"It is a great honor to receive the prestigious Hank Aaron Award," Harper said. "Mr. Aaron is an icon not only in baseball but in American history. It is a privilege to be associated with Mr. Aaron and all the great players that have previously won this award. Thank you to my teammates, the Nationals' organization and my friends and family for all their support."

Video: Harper discusses winning the Hank Aaron Award

Donaldson was thankful as well.

"I feel very fortunate and blessed to be in this situation today," Donaldson said. "Not just being a baseball player, but I've been a baseball fan my entire life. To be able to sit here and sit beside Hank Aaron, just what he's meant to the game, it's a real honor. And you don't really think as a kid, you don't really think you would get to experience moments like this. And it's definitely something I'm very grateful for."

Video: Donaldson on the origins of his Twitter handle

The Hank Aaron Award was established in 1999 to honor the 25th anniversary of Aaron breaking Babe Ruth's all-time home run record. Fans voted on MLB.com and, for the sixth straight year, a special panel of Hall of Fame players led by Aaron also had input.

Past winners include: Giancarlo Stanton and Mike Trout (2014); Miguel Cabrera and Paul Goldschmidt ('13); Cabrera and Buster Posey ('12); Jose Bautista and Matt Kemp ('11); Bautista and Joey Votto ('10); Derek Jeter and Albert Pujols ('09); Aramis Ramirez and Kevin Youkilis ('08); Alex Rodriguez and Prince Fielder ('07); Jeter and Ryan Howard ('06); David Ortiz and Andruw Jones ('05); Manny Ramirez and Barry Bonds ('04); Rodriguez and Pujols ('03); Rodriguez and Bonds ('01-02); Carlos Delgado and Todd Helton ('00); and Manny Ramirez and Sammy Sosa (1999).