San Francisco 49ers

49ers notes: Stout run defense earns Chris Jones more playing time

New England Patriots running back James White (28) recovers a fumble by New England Patriots quarterback Jacoby Brissett (not pictured) as Miami Dolphins defensive tackle Chris Jones (52) looks to recover the ball during the second half of an NFL football game Sunday, Sept. 18, 2016, in Foxborough, Mass.
New England Patriots running back James White (28) recovers a fumble by New England Patriots quarterback Jacoby Brissett (not pictured) as Miami Dolphins defensive tackle Chris Jones (52) looks to recover the ball during the second half of an NFL football game Sunday, Sept. 18, 2016, in Foxborough, Mass. Associated Press

Defensive coordinator Jim O’Neil on Tuesday credited newcomer Chris Jones with helping plug a 49ers run defense that had been by far the leakiest in the NFL this season.

Jones, who was signed earlier this month, started Sunday’s game against the Dolphins in place of injured right defensive end Quinton Dial, and he played 27 snaps. The 49ers held Dolphins running back Jay Ajayi to 45 rushing yards and Miami collectively to 95 yards.

“I thought he gave a boost to our defense,” O’Neil said. “He was rock-solid at the end position for us, took on two (offensive) linemen a lot and allowed (linebackers) Nick Bellore and Gerald Hodges to scrape free to the ball, and I thought he was one the reasons we had so much success in the run game.”

Though the 49ers still rank 32nd in run defense heading into Sunday’s game against the Chicago Bears – they are giving up 178.1 yards a contest – they’ve allowed fewer than 100 yards in two of their past three games. That’s partly due to better cohesion, especially from inexperienced players such as DeForest Buckner, Hodges and Bellore, and to the return of Glenn Dorsey as a full-time nose tackle.

O’Neil also said he made some adjustments to address the team’s run defense, which at one point had been on pace to allow more than 3,000 yards, something that hasn’t been done in the NFL in the past quarter-century.

With the 49ers zeroing in on the run, however, opponents have merely attacked them through the air. The 49ers’ cornerbacks have yet to intercept a pass this season and the last two quarterbacks they’ve faced, New England’s Tom Brady and Miami’s Ryan Tannehill, combined for a 121.4 passer rating.

The 49ers acquired Jones on Nov. 8 after he was waived by the Dolphins. He had been inactive for every 49ers game prior to Sunday’s in Miami.

Though Dial returned to practice Tuesday, O’Neil said that Jones, 26, played well enough to be part of that rotation.

“He’s going to continue to have a role in our defense,” O’Neil said.

Skov’s season over – The 49ers placed linebacker Shayne Skov on injured reserve after hurting his right knee during Sunday’s loss to the Dolphins.

Skov had reconstructive surgery on his knee in 2011 when he was at Stanford. The current injury is believed to not be nearly as severe and will not require surgery. But with only five games remaining, Skov was not expected to play again in 2016.

Safety Marcus Ball was promoted from the practice squad and will replace Skov on the active roster. The team also added linebacker Wynton McManis, who spent the offseason with the 49ers, to the practice squad.

Et cetera – Colin Kaepernick, who can opt out of his contract before the free-agency period begins in March, sidestepped a question about whether he’d want to continue in Chip Kelly’s offense next season. “I’m focused on Chicago this week,” he said. “I’m not thinking that far down the road.”

▪ The 49ers started their week of practice without outside linebacker Eli Harold (foot), receiver Quinton Patton (concussion) and defensive lineman Ronald Blair (undisclosed). Another outside linebacker, Aaron Lynch, continues to come back slowly from a high ankle sprain.

▪ When practice began, the temperature in Orlando was 84 degrees with 53 percent humidity. The forecast Sunday in Chicago calls for a high temperature of 41 degrees with afternoon showers.

Matt Barrows: @mattbarrows, read more about the team at sacbee.com/sf49ers.

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