While staying relatively healthy, the Kansas City Chiefs have gotten the benefit of facing some quarterbacks who were thrust into a starting role because of injuries.
On Sunday, the Chiefs will take on a team that's making a change at that position for a different reason.
Jason Campbell is taking over for the ineffective Brandon Weeden as the visiting Browns face the arduous task of trying to end Kansas City's reign as the NFL's only unbeaten team.
The Chiefs (7-0) have faced opponents with a combined 15-33 record and two were without their starting quarterbacks - Tennessee on Oct. 6 and Houston last week.
Along with starting rookie Case Keenum in place of Matt Schaub, the Texans also lost top running back Arian Foster and linebacker Brian Cushing to injuries as the Chiefs posted a 17-16 victory.
"The best thing about this team, we've had a lot of bad luck in the past; we're taking success the right way, being very humble about it," linebacker Derrick Johnson told the Chiefs' official website. "Character speaks after a win and we will still come back and grind like we're losing. We'll come back and try to get to 8-0. It's a great feeling. We're loving it."
The Chiefs, meanwhile, have only two rookies who are missing and both were likely to serve as backups, tight end Travis Kelce and safety Sanders Commings. That health has helped Kansas City get off to its best start since winning its first nine games in 2003.
"This is a rough business. Injuries do take place. I get it. But we've been fortunate," coach Andy Reid said. "That's really what it is."
The defense has played a significant role in the Chiefs' incredible turnaround from last year's franchise-worst 2-14 finish. Kansas City has given up a league-low 81 points and no more than 17 in any game.
The Chiefs are fifth in average yards given up (304.6) and third against the pass with 194.7 allowed per game. With a league-best 35 sacks, they're on pace to top the 1984 Chicago Bears' NFL record of 72.
That's helped them stay unbeaten with an offense that ranks in the middle of the pack with 24.1 points and 330.7 yards per game.
Kansas City's defense will try to keep rolling against a Browns team that's allowed its quarterbacks to get sacked 27 times, tied for second-most in the league.
Weeden was brought down 21 times in his five games this season. He endured three of those in last Sunday's 31-13 loss at Green Bay while completing just 17 of 42 passes (40.5 percent) for 149 yards.
That performance caused coach Rob Chudzinski to turn to Campbell, who has made 71 career starts and is the third starter this season for Cleveland (3-4) along with the injured Brian Hoyer.
"It's a tough decision," Chudzinski said. "I believe this is in the best interest of the team, and ultimately gives us the best chance to win. I'm excited to see what Jason will do with this opportunity."
Campbell made one start and played in six games for Chicago last season.
"It's an opportunity to go out there and just get back to the game and just having fun," Campbell said. "Obviously, we want to go win games and do the best we can. But at the same time we understand we're a growing football team and our goal and mission every week is to go out and win games."
Campbell helped lead Oakland to wins over Kansas City in 2010 and 2011. The Browns blew out the Chiefs 30-7 in the most recent matchup Dec. 9.
Kansas City's Jamaal Charles opened the scoring in that game with an 80-yard run and finished with 165 yards on 18 carries. He's third in the NFL this season with 561 rushing yards and is tied for second with six touchdowns on the ground.
Charles has a team-leading 36 receptions and Dwayne Bowe is next with 25, but he'll be a game-time decision due to a groin injury suffered in practice Thursday.
Cleveland, which has won three of four in this series, is making its first visit to Kansas City since a 41-34 victory Dec. 20, 2009.