(CNN)For many NFL teams, their hopes of making the playoffs have already been dashed. But for others, the fun has only just begun.
3 things to watch for this NFL Sunday
Going into the third NFL Sunday of the season, teams will look to capitalize on early momentum, correct miscues that have exposed weaknesses or start planning for the 2020 Draft.
This Sunday is particularly intriguing, with a string of relatively unknown backups taking the field, a reigning MVP going head-to-head with a Heisman, and the hapless Dolphins taking on the red-hot Cowboys.
Here's what to watch for:
The season started with a bombshell when Andrew Luck, the top pick from the 2012 NFL Draft, unexpectedly retired from football. The 29-year-old had been long pegged as the long-term quarterback of the future, after taking the reins of the Indianapolis Colts from 14-time Pro Bowler Peyton Manning that same year. In his place, Jacoby Brisset will lead the team against the Atlanta Falcons on Sunday.
Speaking of Manning. Peyton's younger brother, Eli, has been demoted to the bench after starting for the New York Giants since forever, or at least since 2004. Other long-time signal callers that won't play in week three are Drew Brees of the New Orleans Saints and Ben Roethlisberger of the Pittsburgh Steelers, each sidelined with injuries.
Incredibly, this weekend will be the first time since 2003 that one of the trio -- Roethlisberger, Brees or Manning -- will not be starting a game.
Overall, there will be seven backup starting quarterbacks taking the field this week: Teddy Bridgewater for the Saints, Mason Rudolph for the Steelers, Daniel Jones for the New York Giants, Luke Falk for New York Jets, Kyle Allen for the Carolina Panthers and Brisset for the Colts. Gardner Minshew of the Jacksonville Jaguars didn't look like a typical rookie backup when he shined in the Jags' win Thursday night. In fact, Minshew had that post-game swagger after his first NFL victory.
The Jets' Falk said after the teams' loss last week that it will be nice to get some actual snaps, rather than "just the mental reps at practice."
That was a common theme this week for the newbie starters. During media availability on Wednesday, the Saints Bridgewater, calling the start his first "meaningful football since 2015," took reps in preseason, but says "it's nothing like being out there during the games when it counts the most."
Jones, the only quarterback change not due to injury, has the benefit of an experienced teammate in Manning to help him through the start, saying during Wednesday's media availability, "I understand the circumstance and it's a difficult one. But he's (Manning) very supportive of me and I can't say enough about who he is as a person, as a teammate."
WATCH: All but Minshew play on Sunday. Check your local listings.
Baltimore Ravens quarterback Lamar Jackson isn't too far removed from being a backup himself, as the Louisville alumnus took over for Joe Flacco mid-season last year. The Heisman Trophy winner has set the league on fire through the first two games, including a breakout week one performance that saw the Ravens' offense put up 59 points. Jackson has completed an astounding 72% of his passes and has thrown for seven touchdowns in the young season -- already eclipsing his six TD's tossed in 2018.
Jackson's stellar play has caught the eye of this Sunday's opponent, Patrick Mahomes of the Kansas City Chiefs, who said during his mid-week press conference, "It's going to be a great experience (playing Jackson)."
Mahomes, a breakout star himself, recognizes the jump the second-year quarterback has made, continuing, "I understand going from year one to year two. There's a huge switch understanding the offense...and it's let him have more success as a passer."
The Chiefs quarterback spent his rookie year learning under Alex Smith and got the chance to display his talents in the last game of the 2017 season before becoming the league's MVP in 2018.
Jackson, for his part, is equally looking forward to the matchup with Mahomes, stating at his media availability, "He's a dynamic quarterback...I can't wait to compete against him again. Its Ravens versus Chiefs...I'm competing against their defense if anything. And I depend on our defense to do a good job of stopping him."
The Chiefs eked out a 27-24 victory over the Ravens last season, and Jackson will look to lead a strong Baltimore offense in a "revenge" rematch. The Ravens have averaged 41 points a game this season, while the Chiefs are only slightly behind them at 34 points a game.
WATCH: Baltimore Ravens vs. Kansas City Chiefs, Sunday at 1 pm ET on CBS
The 1972 Miami Dolphins are the only team in NFL history to finish a season undefeated.
On the flipside, the 2017 Cleveland Browns and the 2008 Detroit Lions are the only teams to lose all of their games in a 16-game season.
Why is this relevant? Because the once-proud Dolphins, two-time Super Bowl Champions, are facing the possibility of a very defeated season.
Part of this appears to be intentional, in a near imitation of the "Process" utilized by the NBA's Philadelphia 76ers, with the Dolphins starting the year by trading impact players like Laremy Tunsil and Kenny Stills for future draft picks. Just this week, the Dolphins shipped Minkah Fitzpatrick, their top draft pick from 2018, to the Steelers for yet another future draft pick. Between the exodus of talent and the prospect of a winless season, fans on South Beach can't have much hope as a 21.5 underdog to the Dallas Cowboys this Sunday.
Still, Pro Bowler Xavien Howard, one of Miami's standout players, thinks it's too early to count the Dolphins out. Howard brings up this Sunday's game against Dallas as an example, telling the Sun Sentinel: "I went to Baylor right down the street...I have family coming to the game, college teammates...so that's going to motivate me." But beyond that, it comes down to pride for Howard, "the name on the back of my jersey...that's what motivates me."
For their part, America's team is not overlooking their opponent. Cowboys linebacker Jaylon Smith said during the mid-week media availability that his team has to be ready, "It's the National Football League. Everyone's legit. For us, it's about preparing the right way and respecting every opponent."
WATCH: Miami Dolphins vs. Dallas Cowboys on Sunday at 1 pm ET on FOX