The MLPAA selects winners from each of the 30 Major League clubs and then has current and former players vote for an overall winner of the annual award, with the national honor presented on Nov. 10 at the 16th annual Legends for Youth Dinner in New York.
Previous overall winners are David Eckstein (2005), Craig Biggio (2006, 2007), Grady Sizemore (2008), Albert Pujols (2009), Roy Halladay (2010), Torii Hunter (2011), Mike Trout (2012), Dustin Pedroia (2013) and Josh Harrison (2014).
The award honors active players who "demonstrate a passion for the game of baseball and best embody the values, spirit and tradition of the game," according to the MLPAA.
Mariners manager Lloyd McClendon said Seager's selection is well deserved.
"He's a throwback," McClendon said. "He's an old-school type of player. He comes every day and gets dirty and leaves it all out on the field. He tries to get better every day. He comes to beat the other team. He's a great teammate. He epitomizes everything that award is all about."
Past Mariners nominees have been Seager (2014), Raul Ibanez (2006, 2007, 2013), Munenori Kawasaki (2012), Miguel Olivo (2011), Franklin Gutierrez (2010), Jose Lopez (2009) and Ichiro Suzuki (2008).
In typical Seager fashion, he wasn't particularly comfortable talking much about himself or reasons for his selection.
"I don't think anybody sets out to play the game to win this kind of stuff," he said. "You play to win the games and if something like this happens, it's kind of gravy."
But McClendon said Seager's drive and work ethic make him a natural fit.
"I'm sure it had a lot to do with his upbringing," McClendon said. "Probably more to do with life than baseball, how he went about his business as a youngster, certainly the way his parents brought him up. It just carried over to the baseball field."