Seahawks, 49ers both down in the trenches

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The Seahawks might dislike the 49ers — and the feeling would be mutual — but Seattle sure has an affinity for ex-49ers.

The Seahawks will visit Levi’s Stadium on Thursday night with a 53-man roster that includes five players who were released by the 49ers: defensive tackle Demarcus Dobbs, wide receiver Ricardo Lockette, linebacker Nick Moody, wide receiver B.J. Daniels and fullback Will Tukuafu.

Why is 9 percent of their roster made up of players who once competed for their fiercest rival?

“We’re looking for the best competitive players we can find and we’ve obviously been battling with the 49ers for a long time,” Seattle head coach Pete Carroll said. “And we’ve played really tough, physical games. And we have a similar style of running the football and playing defense and maybe there’s some connection in all of that.”

Indeed, the 49ers and Seahawks have been among the NFL’s biggest bullies. They have claimed the past three NFC championships and the past five NFC West titles, thanks to a punishing style: They both ranked among the NFL’s top five in rushing and total defense from 2012 through 2014.

On Thursday, however, each will arrive with a 2-4 record, marking the first time since Dec. 6, 2009, that they’ll meet with each lugging losing marks. There are myriad reasons for the disappointing starts, but their slides from bully to oft-beaten is symbolized by struggles where football is its most physical: Both have had toothless play in the trenches.

The Seahawks’ offensive line, for example, has allowed the most sacks (26) in the NFL and is on pace to surrender 69, which would tie for ninth in NFL history. On Thursday, the Seahawks’ front five will face a defense that ranks 24th in sacks (nine) and has the fewest in the NFL since Week 1. The 49ers have four sacks in their past five games and none in their past two.

Call it the movable force against the inert object?

Seattle Seahawks quarterback Russell Wilson — her fending off Carolina Panthers outside linebacker Shaq Thompson on Sunday, has been pressured on 46.4 percent of his dropbacks. Seattle Seahawks quarterback Russell Wilson — her fending off Carolina Panthers outside linebacker Shaq Thompson on Sunday, has been pressured on 46.4 percent of his dropbacks. Photo: Elaine Thompson, Associated Press Photo: Elaine Thompson, Associated Press Image 1 of / 1 Caption Close Seahawks, 49ers both down in the trenches 1 / 1 Back to Gallery

The 49ers hope to end their sack-less streak against a front featuring two offensive linemen who were playing other positions until recent years. Seattle center Drew Nowack was a defensive tackle at Western Michigan who moved to offense when he entered the NFL as an undrafted free agent in 2012. Right tackle Gary Gilliam, a 2014 undrafted free agent, was a tight end at Penn State before he made four starts at right tackle as a senior two years ago.

Nowack and Gilliam entered the season with one career start. Nowack lost his starting spot last week, but he will return to the starting lineup Thursday because his replacement, Patrick Lewis, is out with an ankle injury.

The Seahawks are still running effectively — they rank second in the NFL with 137.8 yards a game — but quarterback Russell Wilson is running for his life. Wilson has been pressured on 46.4 percent of his dropbacks, the highest percentage in the NFL, according to Pro Football Focus.

“We have young guys that are coming together,” Carroll said. “They had to go through some bumps along the way here as we continue to learn and grow and all that. Something we kind of expected.”

The 49ers should have expected a dip in their defense, which has ranked among the NFL’s top five in yards allowed the past four seasons. This season, however, they rank 31st as they’ve struggled to replace a group that includes defensive tackle Justin Smith and linebackers Patrick Willis, Aldon Smith and Chris Borland.

Outside linebacker Ahmad Brooks and inside linebacker NaVorro Bowman are the only 49ers with 10 or more career sacks, and Bowman referenced the deteriorated roster this week when asked about head coach Jim Tomsula.

“I think him being dealt this hand of players, with the young guys being asked to play such a high-valued (role), I think he’s doing a great job,” Bowman said to Seattle reporters.

For his part, Bowman will be playing against the Seahawks for the first time since his horrific knee injury in the NFC Championship Game in January 2014. After he was sidelined for a season, Bowman ranks second in the NFL in tackles (59), but has struggled in pass coverage. On Sunday, Baltimore quarterback Joe Flacco said Bowman wasn’t moving as well laterally as his did before his injury.

Bowman insists he has taken such critiques in stride and has acknowledged he’s not quite what he once was, which gives him something in common with the two teams renewing their rivalry Thursday.

“I don’t take it too personal,” Bowman said. “I just think they remember what type of player I was and try to nitpick at my flaws now. I think that’s what motivates me and keeps me driving toward getting back to that level.”

Eric Branch is a San Francisco Chronicle staff writer. E-mail: ebranch@sfchronicle.com. Twitter: @Eric_Branch

Seahawks (2-4) vs. 49ers (2-4)

When: 5:25 p.m. Thursday

TV/Radio: Channel: 5 Channel: 13 Channel: 46 NFL Network/680, 107.7

Spotlight on: LB NaVorro Bowman: He said his surgically repaired knee felt the best it had all season in a 25-20 win over the Ravens on Sunday, but he noted the quick turnaround. For the first time in his comeback, Bowman will play two games in five days: “It was the best I felt throughout the season, and then we come around and have a Thursday night game,” Bowman said. “I felt good this last game. Hopefully, I can get the knee ready (Thursday) to feeling the same way it felt this last Sunday.” Bowman is coming off a 15-tackle performance and could be enlisted to cover Jimmy Graham. The 6-foot-7 tight end had 140 receiving yards Sunday after averaging 40.8 in his first five games with Seattle.

Injury notes: Seahawks — LB Bobby Wagner (pectoral) is probable after he was sidelined during Sunday’s 27-23 loss to Carolina. 49ers — WR Anquan Boldin (hamstring), RB Carlos Hyde (foot) and RT Erik Pears are questionable.

The Big 3

The 49ers are 2-5 against the Seattle since 2012. They have averaged 10.7 points, 266.9 yards and 16 first downs in those games.

Starting DTs Glenn Dorsey and Quinton Dial of the 49ers don’t have a sack. Among 23 DTs in a 3-4 defense, they rank at the bottom of Pro Football Focus’ Pass Rush Productivity Rating.

Hyde (430) and QB Colin Kaepernick (228) are the only 49ers with more than 25 rushing yards. Reggie Bush (4 carries, 7 yards) has played in three games and finished just one this season because of a calf injury. He is probable.

— Eric Branch