Andy Dalton and Tyrod Taylor have been pleasant surprises for their respective squads, though one is likely to be limited this weekend.
Despite nursing a knee injury, Taylor is pushing to play Sunday when the banged-up Buffalo Bills try to keep the Cincinnati Bengals from matching their best start.
A year after finishing with 19 touchdowns and 17 interceptions and struggling in a 26-10 playoff loss to Indianapolis, Dalton is off to the best start of his five-year career.
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He's thrown for an average of 303.6 yards with 11 scores and only two picks, giving him a 115.6 passer rating that ranks third in the NFL behind New England's Tom Brady (121.5) and Green Bay's Aaron Rodgers (117.4).
"When you want people talking about you, you don't want them talking negatively about you," Dalton said. "Obviously I've had to bear a lot of it. But we're 5-0 right now, hopefully at the end of the year they're still talking the same way."
Star wideout A.J. Green and tight end Tyler Eifert are benefiting the most from Dalton's emergence. Green is fourth in the NFL with 495 receiving yards, while Eifert is tied for second with five touchdown catches.
Dalton stepped up down the stretch last Sunday, going 13 of 15 for 135 yards in the fourth quarter and overtime as the Bengals rallied from 17 points down for a 27-24 win over Seattle. He finished 30 of 44 for 331 yards with two touchdowns and one interception after a comeback that matched the second-biggest in franchise history.
The Bengals (5-0) are a win away from tying the best start in team history, most recently reached in the 1988 season that preceded their last Super Bowl appearance.
Dalton connected on 26 of 40 attempts for 337 yards with three TDs and one pick in a 27-24 overtime win in the most recent meeting at Ralph Wilson Stadium on Oct. 13, 2013.
Taylor was in his third season with Baltimore at that time and played only one game last year before signing with Buffalo in March. After winning the starting job in the preseason, he's completed 70.1 percent of his passes with nine touchdowns and four interceptions. He also ranks fourth among quarterbacks with 187 rushing yards.
"We know he has that kind of ability to make big-time plays, and whenever we see it's just a momentum changer, it gets the guys on the bench riled up and we're excited for it," defensive end Jerry Hughes said.
Taylor ran for a career-high 76 yards - the most in team history by a quarterback - and a score in last Sunday's 14-13 win at Tennessee. However, he suffered a sprained left knee when he was horse-collared on a tackle in the fourth quarter.
He's been limited in practice and might not be cleared to play until later in the week. If Taylor is unable to go, Buffalo will likely turn to former starter EJ Manuel, who hasn't been under center at kickoff in over a year and is 6-8 in his career as a starter.
"As long as I can sit back there and throw I feel like I can be productive," Taylor told the team's official website. "It's definitely a stability thing, but as far as moving around we'll see how that goes and if it's feeling better. It hasn't limited me much."
Sammy Watkins, who led the Bills in receiving yards in 2014, is likely to play in a limited role after missing the past two games because of a calf injury.
Dan Herron and Anthony Dixon, however, are the only healthy running backs. LeSean McCoy seems unlikely to be back from a hamstring injury despite returning to practice, and backup Karlos Williams needs to pass the league's concussion protocol.
The Bengals have been vulnerable defensively, ranking 22nd against the pass at 262.6 yards per game and allowing Seattle to rush for 200 last weekend.
Offensively, Cincinnati would like to get more out of its rushing attack with only one 100-yard rushing performance so far. Giovani Bernard has run for 63.6 yards per game in his last three, while Jeremy Hill is averaging just 3.0 per carry on the season.
It's not likely to be any easier against a Buffalo defense that ranks third in the NFL against the run (82.2 yards per game) and has yet to allow a 100-yard performance.
The Bills (3-2), though, will be without starting safety Aaron Williams for at least eight weeks because of a neck injury that he aggravated last Sunday.
Buffalo had won 10 straight in this series between 1989-2010 before dropping the past two in 2011 and 2013 by three points apiece.