OAKLAND, Calif. — A slow start to the season and a worse start to the current nine-game road trip has pushed one of the more popular Mariners off the 25-man roster and possibly out of the organization.

On Sunday, the Mariners made two roster moves. The most drastic was designating starting center fielder Leonys Martin for assignment to make room for first baseman Daniel Vogelbach. Seattle also swapped long relief pitchers, calling up right-hander Chris Heston to replace right-hander Chase De Jong, who pitched four innings on Saturday.

Servais informed Martin of the move on Saturday evening.

Martin was hitting .111 with a double, four steals and an anemic .172 on-base percentage and a .130 slugging percentage in 15 games. Swing changes made in the offseason were counterproductive. He struggled to find consistency with them this spring and it carried into the regular season. He tried to switch back to his previous stance in swing at the end of the season-opening road trip, but he was mired in a slump and racked with confidence issues.

With Guillermo Heredia playing well and Jarrod Dyson capable of playing center field, the Mariners decided to make a change. Since Martin was out of options, they had to designate him for assignment. Because he’s owed most of his $4.85 million contract this season, there is a chance that he could clear waivers and be outrighted to Class AAA Tacoma. The Pirates are interested in picking up Martin to offset the loss of Starling Marte to an 80-game suspension. But they are unlikely to pick up his full contract. The Mariners could work out a trade with Pittsburgh and take on some of that money owed.

Vogelbach was inserted into the lineup at first base immediately for Sunday’s series finale against the A’s. With the Mariners expected to face a slew of right-handed starting pitchers in Detroit and Cleveland, he will play extensively.

Vogelbach, 24, was hitting .309 (17-for-55) with three doubles, two home runs, 14 RBIs and an .882 on-base plus slugging in 16 games with Class AAA Tacoma. Over his last 10 games, he’s hitting .351 (13-for- 37) with two doubles, two home runs and 12 RBI.

With Danny Valencia hitting .145 with a .443 OPS, the Mariners had to do something at first base. They will go back to their original plan of using two first basemen.

Heston will serve as a long reliever for the time being, but could go back to Class AAA Tacoma when Steve Cishek comes off the disabled list.

On Monday, the Mariners optioned Mike Freeman to Tacoma to make room for shortstop Jean Segura, who will join the team today in Detriot.