KANSAS CITY -- Mariners general manager Jerry Dipoto added some more offensive punch to his lineup on Sunday, trading Minor League outfielder Boog Powell to the A's for All-Star first baseman Yonder Alonso.
The 30-year-old Alonso is hitting .266/.369/.527 with 22 home runs and 49 RBIs, and he provides a left-handed-hitting option to go with former A's teammate Danny Valencia at first base for a Seattle club pushing for an AL Wild Card spot.
"Yonder fits our roster quite well," said Dipoto. "Obviously, he's had an excellent year to this point, an All-Star season, real breakout year for him. We are acquiring a bat that makes us a difference in the middle of our lineup."
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Alonso is earning $4 million this year and will be eligible for free agency at the end of the season. The Mariners haven't been interested in rental players for the most part, but they're just 1 1/2 games back of the Royals for the second AL Wild Card spot.
"We feel like we're nipping at the heels of the Royals and are right there in the thick of it with Tampa [Bay]," Dipoto said. "Obviously we've done what we can over the course of the last two seasons to continue to be mindful of both the present and future. I believe Yonder is the first true rental we've acquired since I've been with Mariners.
"In this case, it's a guy who fits us not just now, but potentially moving forward. What better way to get to know a player than have him join you?"
Dipoto said the Mariners pursued a deal for Alonso prior to the July 31 non-waiver Trade Deadline, but "couldn't quite push it over the goal line."

Although the July 31 non-waiver Trade Deadline had passed, the Mariners claimed Alonso when he was sent through waivers by the A's, and the two teams were able to finalize a deal on Sunday. The Mariners will be in Oakland on Tuesday to wrap up a 10-game road trip after splitting a Sunday doubleheader in Kansas City.
"Going to a team 1 1/2 games out of the playoff contention, that actually is a lot of fun," Alonso said. "I get to play some meaningful baseball, which it'll be probably the first time in my career to do that."
Alonso said he was surprised to be dealt after the July 31 Deadline passed, but understood the move.
"Now is my next chapter," he said. "They have a winning team and they're playing good baseball and I'm excited to be a part of that."
Alonso has hit .286/.391/.557 against right-handed pitching this year, and he figures to give the Mariners another productive bat for a lineup that struggled with consistency in July.
Valencia had a .256/.300/.389 line against right-handers, while batting .266/317/.418 overall in 102 games entering play Sunday. The Mariners initially planned to platoon Valencia with rookie Daniel Vogelbach this season, but wound up using Valencia exclusively when Vogelbach struggled.
Alonso is a career .268 hitter in eight Major League seasons with the Reds, Padres and A's, and he was a first-round Draft pick of the Reds in 2008 out of the University of Miami.
Powell, 24, returns to the A's organization that drafted him in the 20th round in 2012. The 5-foot-10, 185-pounder hit .194 with six runs in 23 games over three stints with Seattle this season. He spent most of his season in Triple-A Tacoma, hitting .340 with 46 runs, six homers, 33 RBIs and 11 stolen bases in 58 games.
Powell was suspended for 80 games midway through last season after testing positive for a banned substance and missed the first five games this year at the conclusion of that suspension. He was acquired by Seattle from the Rays prior to the 2016 season as part of a six-player deal.