Arik Armstead's injury forces 49ers to reconfigure defensive line

Arik Armstead had dealt with a shoulder surgery since training camp before being put on injured reserve. John Hefti/USA TODAY Sports

SANTA CLARA, Calif. -- The San Francisco 49ers are a little too familiar with the far-reaching consequences of serious injuries.

Season-ending injuries to the likes of linebackers NaVorro Bowman and Ray-Ray Armstrong have forced the Niners to revamp their linebacker corps. Shorter-term health problems in the secondary have done the same.

Now, with second-year defensive tackle Arik Armstead out for the season because of a shoulder injury, the 49ers will have to adjust again up front.

“I think any of those guys have to see an increased role," coach Chip Kelly said. "You’ll see Quinton Dial a little bit more at defensive end. We had tried to move Quinton in at the nose. I think you’ve got to kind of go with a [Glenn] Dorsey, [Mike] Purcell rotation at the noseguard spot. Then you’ve got DeForest [Buckner], Ronald [Blair], Tony Jerod-Eddie and Quinton will be your defensive ends as we move forward.”

The 49ers haven't been averse to moving their defensive linemen around anyway with Dial jumping into the middle as well as working at end and Buckner occasionally lining up inside on passing downs as well. Blair and Jerod-Eddie have been used more sparingly but figure to get more snaps moving forward behind Buckner and Dial.

As for Armstead, his shoulder injury had been something he was dealing with since training camp. He managed it by wearing a harness in games but he apparently aggravated it enough in last week's loss to the New Orleans Saints that the Niners thought it best to shut him down for the season.

“I just know that his shoulder is different than it was before," Kelly said. "He met with the doctors and our training staff on Monday. From what I understand, they went through an MRI and then Arik, [vice president of football operations Jeff Ferguson] and doc decided that the best option for him at this point in time after that MRI was to get operated on.”

Armstead is expected to have that surgery in the near future though Kelly wasn't sure of an exact date.

"I think within the week," Kelly said. "I don’t know what the operation days are. Somebody said it was a Tuesday-Thursday thing, but I don’t know. May have missed the window on it. If not, it’ll be done by next week from what I understand, what I gather.”

In the meantime, the Niners will also work to get newly acquired defensive lineman Chris Jones up to speed. The team claimed Jones off waivers from Miami on Tuesday, and he arrived on Wednesday, though he didn't make it in time to participate in practice.

Jones was a sixth-round pick of the Houston Texans in 2013. He has spent time with Tampa Bay and New England in addition to Miami. In 35 career games, Jones has 85 tackles and nine sacks.

“Obviously he’s played in this league," Kelly said. "He played for the Patriots and he played for the Dolphins. When you’re picking up players at this point in time during the year, it’s really what’s available, not ‘Hey, I really like that guy.’ Well, that’s great. He’s under contract with another team. We were fortunate that he became available. Hopefully, it’s good timing because we got a chance to get him, but until we get to see him run around and do some things before we can determine exactly how he’ll fit in terms of what we’re doing.”