SAN FRANCISCO — One year after pitching a no-hitter, right-hander Chris Heston was traded from the San Francisco Giants to the Seattle Mariners on Wednesday for a player to be named.

The Giants did not have a spot for the 28-year-old in their rotation featuring Madison Bumgarner, Johnny Cueto, Jeff Samardzija, Matt Moore and Matt Cain. Seattle's need for additional rotation depth made the Mariners a perfect partner.

After going 12-11 as a rookie in 2015 and no-hitting the Mets on June 9 that year, Heston spent most of this season in the minors, making just four appearances for San Francisco. He went 1-1 with a 10.80 ERA in five innings of relief.

Heston showed enough as a rookie for Seattle to view him as a worthwhile option for its starting staff. The Mariners' rotation was thinned significantly when they traded Taijuan Walker to Arizona last month in a deal that brought back shortstop Jean Segura. Segura filled a crucial hole, but his acquisition came at a significant cost in Walker.

Seattle's rotation for next season now includes Felix Hernandez, Hisashi Iwakuma and James Paxton as certainties, leaving Ariel Miranda, Nathan Karns and Heston as the trio likely to compete for the final two spots.

To open a roster spot, Seattle designated infielder-outfielder Richie Shaffer for assignment.