PITTSBURGH — The Pittsburgh Steelers will be without key starters on their offensive and defensive lines when they face the Jacksonville Jaguars on Sunday.

Right tackle Marcus Gilbert will miss his fourth straight game with a knee injury, while defensive end Stephon Tuitt has been ruled out with an elbow injury. Second-year player Matt Feiler will fill in for Gilbert as he has the past three weeks, while nine-year veteran Tyson Alualu is set to replace Tuitt.

"I think you just always have to be ready and be prepared when you do get opportunities to play more," Alualu said. "You just have to make sure there's no drop-off when someone goes out, especially with it being Tuitt because we all know what he's capable of and what he's done."

Gilbert has only played 13 of the team's last 25 games after missing just three games the previous two seasons.

It will be Feiler's fifth start of the season and sixth of his career. He has already started four games this season. The first came in Week 3 against Tampa Bay, the Steelers' first win of the season, when Gilbert sat with a hamstring injury.

"I'm just trying to stay ready because you never know when they're going to need me," Feiler said. "I've just been preparing like I have been every week like I'm going to be playing."

The Steelers have won all four times Feiler has started at right tackle, including the last three games. Those wins were part of a five-game winning streak that has helped the Steelers climb atop the AFC North after a 1-2-1 start.

The Steelers have averaged 424 yards of total offence the previous three weeks, including 140 on the ground. James Conner, third in the league with 771 rushing yards and 10 touchdowns, has rushed for more than 100 yards in two of the last three weeks. Conner will play Sunday after leaving last week's win against Carolina with a concussion.

"Every lineman wants to run-block and kind of push other guys around," Feiler said. "We've been clicking. We've been staying on the field longer and keeping our momentum. It's a lot of fun."

Alualu will get the start against Jacksonville, a city where he spent his first seven seasons before signing with the Steelers.

The Jaguars shocked the Steelers on the road, 30-9, last season and did it again in the playoffs, winning 45-42 in Pittsburgh before falling to New England in the AFC Championship game.

Leonard Fournette rushed for 290 yards and five touchdowns in those two games against the Steelers. He missed six games because of injury this season before returning last week during a loss at Indianapolis. The Jaguars have lost five of those six and are 3-6, last in the AFC South.

"Their record doesn't show how hard they're playing," said Alualu, who has exchanged texts with former teammates. "The guys in the locker room are still fighting. We have to understand that we're going to get their best."

During the win streak, the Steelers' defence has allowed an average of 269 yards of total offence, including 70 on the ground. In their first four games, they gave up an average of 418 yards, including 115 rushing.

Tuitt, who has appeared in all nine games, is key part of Pittsburgh's pass rush, which is tied for second in the league with 31 sacks. Tuitt has 32 tackles, three sacks, four tackles for loss and 11 quarterback hits.

Alualu hasn't reached the quarterback yet this season, but he finished with a career-high four sacks mainly in a reserve role in 2017.

"It's a good problem to have when you have good depth," Alualu said. "That's always helpful."

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