OAKLAND -- Hoping to spark their struggling offense, the Mariners recalled rookie first baseman Daniel Vogelbach from Triple-A Tacoma on Sunday and designated Leonys Martin for assignment, a surprising move given that Martin was the starting center fielder until being benched the last two games.
Vogelbach started at first base in an 11-1 victory over the Athletics. He finished 1-for-4 with an RBI single and a walk. 
The club also optioned pitcher Chase De Jong back to Tacoma and recalled fellow right-hander Chris Heston to give the bullpen a fresh arm after De Jong threw four scoreless innings in Saturday's 4-3 loss to the A's.

"Those decisions are hard. I really like Leonys," manager Scott Servais said. "He's a big part of what we're doing here. Unfortunately, he really hadn't got going offensively and if you date back to the second half of last season, and he really struggled through Spring Training and he got off to the rocky start this year. We want to let some other guys play. Guillermo Heredia and some other guys we have, offensively, have the opportunity to do a little more than Leonys was doing."
Vogelbach, the Mariners' No. 9 prospect per MLBPipeline.com, posted a .309/.409/.473 line with two homers and 14 RBIs in 16 games for Tacoma. The 24-year-old was expected to split first-base duties this year with veteran Danny Valencia, but he instead started the season in the Minors after struggling in Spring Training.
But with Valencia hitting just .145/.217/.226 with no homers and four RBIs in his first 18 games for Seattle, Vogelbach will be given another shot with the big league club.
"I went down there with a purpose, to get better, and I'm starting to feel much better at the plate," Vogelbach said. "I went down there and had fun and we won. Now I'm here and this is what we want to do. I'm just going to try to be myself, have fun and start winning some ballgames."
Martin, 29, has struggled even more than Valencia in the first three weeks of the season and was batting .111/.172/.130 with 14 strikeouts and no homers or RBIs in 54 at-bats after hitting .247/.306/.378 with 15 homers and 47 RBIs last year.
Martin is an excellent defensive center fielder, but the Mariners have a strong option there with speedy left fielder Jarrod Dyson, who will now move over to the regular center-field spot. Heredia has played well in limited duty in left field when Dyson has played more center recently, and Heredia presumably will get regular time there going forward.

Martin is making $4.85 million this year and would have been arbitration-eligible one more season before becoming a free agent in 2019. Instead, the Mariners now have seven days to trade or release him. If he clears waivers, he could potentially remain with Seattle in its Minor League system. But there are teams, including the Pirates after losing Starling Marte to an 80-game suspension, that could be interested.
Martin was a popular figure in the Mariners' clubhouse, which was very quiet prior to Sunday afternoon's game with the A's. But having struggled out of the gate, general manager Jerry Dipoto clearly isn't waiting long to make changes.
"It's the do-good league," Servais said. "I say it all the time. We want guys that have good process and good at-bats, and if that's not happening, you have to look at how long has this been going on and where are we at. The expectations for our club are very high, as they should have been. We talked about it in Spring Training. I thought we were ready for it, and we haven't played that well on the road particularly. We have to pick it up."