A day earlier, Seager was listed on many of the "All-Snubbed" teams as a deserving candidate who didn't get one of the 33 spots on the initial American League roster. But the Mariners had an idea that Seager was on the short list if anything opened up, and on Monday he was selected to replace injured Blue Jays first baseman Edwin Encarnacion.
Seager becomes the third Mariner selected for the July 15 game at Target Field in Minneapolis, joining second baseman Robinson Cano and pitcher Felix Hernandez. The club is holding out hope that closer Fernando Rodney, who leads the American League with 25 saves, could also be added in the coming days if any pitchers opt out.
The Mariners had three All-Stars in 2011 when Hernandez and closer Brandon League were joined by another late addition, rookie pitcher Michael Pineda. They haven't had more than three All-Stars since getting five in 2003.
Seager, whose offensive numbers are on par with any third baseman in the AL in the first half at .274 with 21 doubles, 13 home runs, 59 RBIs and a .483 slugging percentage, will be making his first All-Star appearance.
"This is obviously a dream come true," said the 26-year-old from North Carolina. "Everybody grows up and you want to play in the big leagues and be an All-Star. For that to happen is pretty special. It's something I'm very proud of and very honored.
"It hasn't really set in quite yet," Seager said. "Everybody keeps asking me about it and talking about it and I got a bunch of texts and stuff. It's one of those things where once I'm there, it'll really set in, once you're in the locker room with all those guys. But thankfully, we're playing really good right now and I can just focus on that."
Seager was stunningly consistent the past three years -- batting .258 in 2011, .259 in 2012 and .260 in 2013 -- and was one of the Mariners' steadiest run producers the past two seasons once he became the club's full-time third baseman.
But after enduring a slow start to this season when he hit .156 with no home runs and two RBIs in the Mariners' first 20 games, Seager has busted loose with a .304/.365/.549 line with 13 homers and 57 RBIs since.
McClendon has pushed Seager to be a more consistent hitter and to punish teams that shift against his left-handed stroke, adding that the results are starting to come.
"We all know he's capable of hitting the home run," McClendon said. "But I want him to be that tough out, particularly with runners in scoring position and when there's a tough guy on the mound and you're able to hit the ball the opposite way for a base hit. And he's starting to do that. I think teams are starting to become leery of shifting him because he's shown he's capable of hitting the ball the other way. He's starting to become that complete player."
Cano has found a kindred spirit in Seager, who said at the start of Spring Training that he planned to take in as much information as he could from working with and watching one of the game's best left-handed hitters.
"The first thing I learned was what a good person he is," Cano said. "He's a great guy. He doesn't talk that much, but he's funny and he works really hard. You can see it every single day. He's never late, he really cares about the game and wants to win. Those are the guys that make a team better.
"I get along good with him," said Cano, who'll be making his sixth All-Star appearance. "I always make fun of him and joke with him, but he knows that I love him. He's a great kid and hopefully he continues doing what he's doing, not only this year but the rest of his career. I know he's going to get better and better because I know how hard he works and he wants to be the best."
Seager said the chance to go to his first Major League All-Star Game with Cano and Hernandez just makes it all the sweeter.
"I've obviously played with Felix a couple years now and got to know Cano pretty well here," Seager said. "To go with a couple guys I know will be good. I can basically be like, 'I am here,' and just kind of follow Cano around. So it will work out well for me."
Seager will also be joined at the All-Star festivities by his younger brother, Corey Seager, a first-round Draft pick of the Dodgers in 2012 who is playing in Sunday's Futures Game in Minneapolis as one of baseball's top young prospects.