PHILADELPHIA -- The hits keep coming for the Mariners, but that's not a good thing when they involve your pitching staff. Veteran right-hander Hisashi Iwakuma became the fourth starter to be sidelined by injury when he went on the 10-day disabled list Wednesday due to right shoulder inflammation.
Iwakuma had been scheduled to start Thursday's series opener in Toronto, but rookie right-hander Chase De Jong will move up a day to take that spot and Christian Bergman will get his first Mariners start in Friday's game that originally was targeted for De Jong.
Seattle has yet to name a starter for Saturday as it pieces things together with a rotation that is now minus Felix Hernandez, James Paxton, Drew Smyly and Iwakuma. The only original starter remaining is veteran Yovani Gallardo, though Ariel Miranda has also been in the rotation since Smyly went on the DL in the final week of Spring Training.
De Jong has made two starts in place of Hernandez, who is due back later this month as he deals with bursitis in his shoulder. Bergman was called up last weekend and pitched long relief on Sunday in his first outing for the Mariners. Dillon Overton made his first start for Seattle in that game in place of Paxton, who is out another week or two with a strained left forearm.

Smyly is on the 60-day DL with a left elbow issue that will likely sideline him until midseason.
"Four out of five," manager Scott Servais said. "I haven't [seen anything like it]. But I've said many times early this year and I'll say it again. They keep playing our games. We have to play our schedule. We have to keep going.
"Our team is very resilient. The guys like each other, they play hard and keep grinding. Lately our bullpen has been really good to keep us in games and let our offense rally. Everybody just has to do their part."
Iwakuma's shoulder situation is a surprise as the 36-year-old had been pushed back two days already due to a bruised left knee after taking a line drive off his leg in his last outing on May 3 against the Angels.

Through interpreter Antony Suzuki, Iwakuma said the shoulder had bothered him his past couple starts and was further aggravated as he's tried to work around the knee issue, which affected the timing of his mechanics and delivery.
"I'm being pretty optimistic about it," he said. "I'll go back to Seattle for an MRI and see what they say."
"He just didn't feel he was ready to post," said Servais. "He's a pro, a veteran, and we have to trust those guys to know when they're ready."
The Mariners called up right-hander Sam Gaviglio from Triple-A Tacoma to fill Iwakuma's spot on the 25-man roster and transferred right-hander Evan Marshall to the 60-day disabled list with a strained right hamstring so they could add Gaviglio to the 40-man roster.
Gaviglio, 26, will pitch in long relief. He's 2-3 with a 3.31 ERA in five starts for the Rainiers this year. His first appearance with Seattle will be his Major League debut.
Marshall, 27, was claimed off waivers from the D-backs and made six relief appearances before being placed on the disabled list on Thursday after his hamstring popped on his second pitch when he was called in Wednesday in the 11th inning to replace injured teammate Jean Machi. He allowed eight earned runs in 7 2/3 innings this season with the Mariners.