With Ben Roethlisberger out indefinitely, the Pittsburgh Steelers remain confident putting another veteran under center.

Making his fourth start in two seasons, Michael Vick appears poised to help lead the host Steelers to a third straight victory and extend the worst start in the history of the winless Baltimore Ravens on Thursday night.

Roethlisberger, who has missed 17 games in his 11-plus seasons, suffered a sprained MCL in the third quarter of Sunday's 12-6 win at St. Louis. Coach Mike Tomlin wouldn't put a timetable on a return for Roethlisberger, who completed 75.3 percent of his passes for 912 yards in two-plus games.

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However, Tomlin and the Steelers (2-1) aren't too concerned about anything past this week.

"He is going to be out for a number of weeks," Tomlin said.

"I'm not worried about the rest of the season, to be honest with you."

The focus shifts to the 35-year-old Vick, who joined the Steelers in late August. He looked rusty at times while going 5 of 6 for 38 yards in place of Roethlisberger on Sunday, but did guide Pittsburgh to a late fourth-quarter field goal.

''This isn't his first rodeo,'' Tomlin said of Vick, whose lone victory in three starts last season for the New York Jets came against the Steelers.

A four-time Pro Bowler, Vick will serve more as a game-manager than gamebreaker while at the helm for the time being.

''I won't put it all on my shoulders,'' he said. ''I'll take sole responsibility of everything that happens, but I'm just going to prepare myself and get myself in the position to help this football team.''

Le'Veon Bell and Antonio Brown should help make Vick's job a little easier.

''He's a leader and he's been doing it for a long time,'' said Brown, second in the NFL with 436 receiving yards. ''It's not only about him. We've got to be able to help him, catching passes, got to be able to run the ball, protect the ball and help him out.''

Bell had 132 total yards and ran for a score last weekend in his return from serving a two-game suspension for violating the NFL's substance abuse policy.

Brown has recorded 20 receptions for 261 yards and a TD in the last two home games against Baltimore (0-3), including last season's 30-17 loss in the AFC wild-card matchup. Bell was held to 79 yards and no touchdowns on the ground but had 86 and a TD receiving in last season's two regular-season meetings with the Ravens.

A perennial top-10 defense, Baltimore has struggled since losing star linebacker Terrell Suggs to a season-ending Achilles' injury in the 19-13 loss at Denver in Week 1. In losses to Oakland and Cincinnati, Baltimore has yielded 65 points and 723 passing yards.

Prior to this season, Baltimore had never dropped its first three games.

''It's a really tough situation for us. We have to grind our way, fight our way out of this,'' Baltimore guard Marshal Yanda said.

Despite their recent defensive struggles, the 23 penalties that plagued them over the past two weeks and a ground game that's averaged 3.3 yards overall, coach John Harbaugh publicly feels his group can turn things around and perhaps be the first team since Buffalo in 1998 to reach the playoffs after opening 0-3.

''We're a very confident football team,'' said Harbaugh, whose team has been in position to win in the fourth quarter in all three games. ''We feel like we can overcome any adversity. We have before, and we will again.

"We've just got to get better at what we're doing, across the board."

Harbaugh and the Ravens believe a quick turnaround from Sunday's 28-24 home loss to the Bengals could help their cause.

''You do like to get right back at it, there's no question about it, win or lose,'' Harbaugh said. ''But especially when you lose, you want to get right back at it and get a chance to redeem yourself. The guys are excited about that.''

Facing a rival also helps.

''We don't have a choice,'' receiver Steve Smith said. ''Let's go down there. We're going to Pittsburgh. That's going to be a physical, bullish kind of game.''

Smith has been one of Baltimore's few bright spots after catching 23 passes for 336 yards in the last two games. He had 186 yards and two TDs against Cincinnati.

He posted five receptions for 101 yards in last season's playoff victory at Pittsburgh.

Joe Flacco has thrown for 746 yards and four TDs in the last two contests but has also been picked off once in each. Including the postseason, Flacco's thrown 13 touchdowns and two interceptions while winning six of the last nine against the Steelers.

It's uncertain if he will line up against injured Pittsburgh linebackers Ryan Shazier (shoulder) and James Harrison (thumb).

Regardless, the Ravens have one focus.

"This is a must-win for sure," Baltimore linebacker Elvis Dumervil told the team's official website. "We won't quit, and you can guarantee that Pittsburgh, (it will) get our best shot."