SANTA CLARA Linebacker Patrick Willis said Thursday he's looking forward to playing a more traditional style of defense for the 49ers on Sunday.
The Seahawks' offense is likely to oblige.
Seattle running back Marshawn Lynch has surpassed 100 rushing yards the past three times he's faced the 49ers, most recently a 111-yard, one-touchdown effort in December at Century-Link Field.
The defensive front Lynch faces Sunday, however, will be a bit different than he's seen in the past. For one, Justin Smith will be back in the lineup at right defensive end. He missed last year's game in Seattle, a 42-13 blowout win by the Seahawks, after partially tearing his triceps tendon the previous week in New England.
"It was a big factor," Willis said of Smith's absence. "To me, he's one of the best defensive players in this game and shows it week in and week out. And anytime he's not out there, we miss him. There's no question about that."
The 49ers also will have a different lineup at nose tackle. Isaac Sopoaga and Ricky Jean Francois, now with the Eagles and Colts, respectively, have been replaced by Ian Williams and Glenn Dorsey. Williams is expected to make his first start Sunday, although Dorsey likely will be platooned into the game.
Willis said Williams is similar in style to Aubrayo Franklin, who played in front of Willis from 2007 until 2010. In two of those seasons, Willis led the NFL in tackles. Franklin is now with the Colts.
"In just being able to move, real low center of gravity, real strong at the point," Willis said of the similarities between Williams and Franklin. "I'm really excited to see him work him and Glenn both. They've worked hard all offseason. Just seeing how they've improved from Day 1 until now. I'm excited. I'm excited to be running some base (defense)."
The team's base defense was almost nonexistent in Sunday's opener against the Packers. Green Bay used three or four wide receivers on 57 of their 62 plays, forcing the 49ers into their nickel or dime defenses, which don't include a nose tackle, for most of the game.
The Seahawks struggled to establish the running game in Week 1, with Lynch gaining only 43 yards in a win over Carolina. He only had one game last season with fewer yards 41 in Week 6 vs. New England.
Last year, he averaged 4.8 yards a carry against the 49ers, and defensive coordinator Vic Fangio likened Lynch to Pro Football Hall of Fame running back Emmitt Smith.
"Because Emmitt ran with power, and elusiveness and slashing-type running without great speed," Fangio said. "That would be the one guy that came to mind."
Injuries As was the case Wednesday, running back LaMichael James (knee) was the only 49er who did not practice. Look for him to miss his second straight game Sunday.