OAKLAND, Calif. — In the midst of the AL wild card chase, the Seattle Mariners will be without starter Felix Hernandez for three to four weeks because of bursitis in his right shoulder.

General manager Jerry Dipoto gave the update on Hernandez on Tuesday.

Hernandez was scratched from his scheduled start last Saturday in Kansas City and placed on the disabled list due to discomfort in his pitching arm. He returned to Seattle and was examined by team physician Dr. Edward Khalfayan.

Marco Gonzales, acquired in a trade with St. Louis last month, took Hernandez’s spot in the rotation. Hernandez is 5-4 with a 4.28 ERA in 13 starts this season. Hernandez missed nearly two months earlier this season because of shoulder inflammation.

“Obviously disappointed to lose Felix,” Mariners manager Scott Servais said. “It’s probably three to four weeks, but hopefully we can get that shoulder calmed down.

“We certainly need him in our rotation. We’re going to be playing a lot of big ball games here in September and we’d love to get him back at that time, but he’s going to have to work his tail off, get the arm strength back. Hopefully it won’t be that long, but three to four weeks is a little bit of a blow there.”

Seattle also placed right-handed reliever David Phelps on the 10-day disabled list with an impingement in his right elbow. He’s expected to miss two to three weeks.

“I think it’s positive on David Phelps,” Servais said. “We’ll get him back relatively soon, 10 days to two weeks. He did the right thing the other day kind of alerting us he didn’t feel right so we got him out of the game before something else was worse.”