Eagles quarterback and MVP front-runner Carson Wentz will miss the rest of the season with an ACL tear. This is bad news for anyone who enjoyed watching him play, it’s bad news for a league that’s running out of healthy superstars, and it’s bad news for Philly fans banking on the second-year signal-caller leading their team to the promised land. But does Wentz’s injury really take the Eagles out of Super Bowl contention? Opinions on that vary—and what you believe probably correlates closely to which version of Nick Foles you expect the Eagles will get.

There’s the version of Foles that came on in relief of Michael Vick to start 10 games for Chip Kelly’s Eagles in 2013, throwing 27 touchdowns and just two picks at an absurd 9.1 yards per attempt for a team-record and league-best 119.2 passer rating. Foles led Philly to an 8-2 record and a playoff berth, was named to the Pro Bowl, and won Offensive MVP honors in the game (and a very cool GMC SUV). It might feel like we got caught in a bizarro alternate universe the year all that happened, but if that guy suddenly shows up, it’s reasonable to think that Wentz’s injury won’t make a big dent in Philadelphia’s claim for the title: This is still a team with a hounding, versatile defensive line, a playmaking special teams group, and a talented set of skill players. And if Foles can attack downfield, efficiently distribute the ball to his arsenal of weapons, and avoid turnovers, the Eagles will remain one of the favorites for the Super Bowl.

The only problem is that the version of Foles we saw that year is an extreme outlier in his otherwise underwhelming career. He fell back to earth in 2014, was traded to the Rams in 2015, and was released one season later. He served as a backup to Alex Smith in Kansas City last year before signing back on with Philly during the offseason. In the 26 games (including 20 starts) since he won that sweet GMC, the 6-foot-5, 244-pound signal-caller has thrown 23 touchdowns and 20 picks at 6.6 yards per attempt for a 77.6 rating. He’s often displayed poor footwork and lacked accuracy and velocity on his throws. At best, the version of Foles we’ve seen the past few years is a decent veteran backup-level quarterback, and overwhelming recent evidence and basic logic would point to the idea that this is the version of Foles that will show up for Philly down the stretch. In that scenario, the Eagles would still have plenty of balance and a plethora of playmakers on offense, but their margin for error against some of the NFC’s elite teams would shrink to microscopic levels.

But is there any reason for hope that this year’s Philly squad can re-create that perfect storm that launched peak Foles in 2013? After all, the Eagles have a varied and explosive run game under Jay Ajayi, LeGarrette Blount, and Corey Clement. They’ve got a big, playmaking pass catcher on the outside in Alshon Jeffery, a speed threat down the field in Torrey Smith, and a dynamic weapon over the middle in Nelson Agholor. They’ve got three starting-caliber tight ends in Zach Ertz, Brent Celek, and Trey Burton. And most important, they’ve got an innovative offensive play-caller in head coach Doug Pederson, who has not been afraid to mix college spread-offense schemes with West Coast offense, pro-style concepts. That’s the same type of situation that helped Foles thrive under Kelly in 2013, when he could alternate among tossing bombs downfield, throwing out of read-option play fakes, and confounding the defense with run-pass option plays at a lightning-quick pace. These RPOs were just one piece of the Eagles’ offensive puzzle that year, but they helped create impossible decisions for defenders: Foles would have the option to hand off, carry the ball himself, or throw the ball depending on what a certain targeted defensive back or linebacker was doing in a given situation. In Philly’s 49-20 blowout win against the Raiders that season, Foles tied an NFL record with seven touchdown passes, and one of those was set up with a play like this:

Against the Bucs, he saw a numbers advantage open up on the left, and while he could’ve handed off to LeSean McCoy on a run to the right, he instead threw a quick pass out left to Riley Cooper, who made two guys miss to find open field.

Flash forward to the present, and the Eagles lead the NFL in RPO plays (155), per Pro Football Focus, by a long shot—Pederson has called 37 more of those option plays than his former mentor, Andy Reid, has run in Kansas City. With Foles’s experience under both Reid and Pederson, he’s been schooled in those types of plays. The question is whether or not he can match the speed with which he processed everything in his outlier year. On Sunday, the Eagles ran a few RPOs with Foles. On one, he handed off to Ajayi, who picked up a few yards.

The decision to hand off worked well enough, but on another similarly schemed play, Foles appeared to be about a half beat too slow, and against an über-athletic Rams front that features destroyer of worlds Aaron Donald, that half beat can be the difference between a successful play and a miscue.

It’s also worth noting that the Eagles didn’t totally abandon RPO concepts after Foles’s wildly successful 2013 campaign (nor did they change the rest of the offense significantly). Foles just never found the same type of rhythm and success as he did that first year under Kelly. Perhaps it was because of Kelly’s overly predictable play-calling, or other teams improving in their ability to counter Philly’s up-tempo tactics, or an incremental but important drop-off in the talent around him (Philly released DeSean Jackson), or any of the million reasons a quarterback regresses following a historic season. In any case, the RPO does not have the capability to magically unlock Foles’s potential, but it may be a tool that Pederson can still use to create favorable situations and easy throws for his backup quarterback.

No championship team can rely solely on those plays, though. All quarterbacks are going to be judged by their ability to step up into the pocket, under pressure, and deliver passes downfield on third down when the defense knows a pass is coming and play-action is rendered useless. Foles did show at least a glimmer of that potential late in the win against the Rams, hitting Agholor on a whip route to the right on a key third-and-8 with 1:52 remaining—a play that allowed the Eagles to run the clock down to seven seconds before punting it away, giving L.A. just one second to try a doomed Hail Mary.

It’s easy to look at what Case Keenum has done with the Vikings this year as proof that anything’s possible for Foles and the Philly offense. On one hand, it’s true that Keenum has performed well past expectations and Minnesota remains a Super Bowl contender with a similar formula for success: a strong run game, an elite defense, and an efficient, low-volume passing game. But on the other hand, Foles isn’t the same type of quarterback as Keenum, whose underrated mobility and effectiveness in the play-action passing game has allowed him to thrive behind a retooled and banged-up Vikings offensive line. Keenum has shown the ability to not only throw off bootleg fakes, but to slide around the pocket, strafe to one side or the other to avoid the pass rush, and reset his feet to throw. This is the same attribute that’s helped make Wentz an MVP candidate this year, and he’s compiled a veritable highlight tape of Houdini escapes and superlative pocket movement prior to big throws this season. The slow-footed Foles just doesn’t have that facet to his game. In 12 passing snaps of relief duty against the Rams, Foles was under pressure five times—and without that innate ability to escape and avoid the pass rush, Pederson’s going to have to scheme up plays that get the ball out of his backup quarterback’s hands a little more quickly. That may mean more check-downs and screens and fewer deep shots.

It seems both reasonable and obvious that the Eagles offense is going to change, and not for the better. Foles is a major step down from Wentz, and that downgrade will shrink the playbook, stifle the team’s ability to create explosive plays through the air, and, almost surely, diminish their ability to score points. But Philly still has a strong run game to lean on, and the trade for Ajayi back in October could end up being the most crucial move the team made this year. Pederson should make Ajayi the foundation of the offense, throw in changeups with Blount and Clement, and limit what he asks Foles to do. The team’s defense and elite front four should help keep most games low scoring, and the top-tier special teams unit is always capable of making a game-changing play. In other words, the Eagles are certainly still contenders, and with an easy slate of defenses down the stretch (at the Giants, at home against the Raiders and Cowboys), the no. 1 seed and a first-round bye are still well within reach. The Eagles aren’t likely to win many games because of Foles, but they’re still balanced enough to compete with anyone.