Whether J.J. McCarthy starts against Eagles is about more than his ankle

At this moment, heading into the Vikings' bye week, it's anyone's guess as to whether Carson Wentz or J.J. McCarthy will start at quarterback against the Eagles on Oct. 19.

Both QBs are dealing with injuries, so health will certainly be a major factor. McCarthy has missed three games with a high ankle sprain, while Wentz came out of the London game with a banged-up left shoulder. But assuming Wentz's shoulder is fine, whether McCarthy returns to the starting role against Philadelphia will be determined by more than the status of his right ankle.

Clearly, the first bar for McCarthy to clear in order to put himself in consideration for the Week 7 start is to show that he's back to full strength. He needs to get in a full week of practice and demonstrate that he can drive off of his back ankle while throwing the ball, as well as move around athletically without any issues.

But that alone won't be enough.

What Kevin O'Connell and the Vikings also need to see from McCarthy is evidence that he's learned from what went wrong in his first two starts and that he's ready to effectively operate their offense upon his return. That starts, at a basic level, with the fundamentals of his lower-body mechanics. He needs to be dropping back with proper technique and tying his feet to his eyes as he goes through progressions. And then he needs to get the ball out of his hands a lot quicker than he did in his first two NFL starts against the Bears and Falcons.

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McCarthy salvaged a win in his debut with an incredible fourth quarter in Chicago, but his other seven quarters were largely awful. He threw three interceptions and took nine sacks on 55 dropbacks for an unsightly 16.4 percent sack rate. Among the 37 quarterbacks with at least 50 dropbacks this season, McCarthy ranks 35th in passer rating and success rate, and he ranks 36th in adjusted EPA per play and completion percentage over expected (CPOE). Cam Ward and Joe Flacco are the only QBs who have arguably been worse.

It was just two games, so it's certainly nowhere near time to overreact or panic about McCarthy's long-term outlook. He displayed a lot of promising signs throughout training camp, and he needs game reps to develop and show what he can do. But at the same time, O'Connell isn't going to play McCarthy if he doesn't think the 22-year-old is ready to have success, because doing so could risk harming his development.

Being injured over the past three weeks gave McCarthy an opportunity to step back and learn from watching veteran backup Carson Wentz, who played very solid football in leading the Vikings to a 2-1 record. In that same sample of QBs, Wentz ranks 17th in passer rating, 13th in adjusted EPA per play and success rate, and sixth in CPOE.

Wentz, who has a 10 percent sack rate, was far from perfect over the last three weeks. But he played in rhythm and got the ball to his playmakers, most notably Justin Jefferson (22 catches for 324 yards). A key stat is that Wentz averaged 2.59 seconds to throw (tied for sixth-quickest) after McCarthy was at 3.08 seconds in the first two weeks (fifth-longest).

There are a lot of things from Wentz's tape that McCarthy can use to aid his own improvement when he returns to the field, whether that's in Week 7 or not.

"He's had some real moments of growth through this time," O'Connell said of McCarthy on Monday. "I think watching Carson, watching the way Carson's kinda gone through progressions quickly, just the value of putting the ball in play, even when it's not your first progression, even when it's not the most exciting completion of all time. ... I think he's kinda taken a lot of that, of just watching it closely and my dialogue with him.

"But I think the most critical part is gonna be technique and fundamentals of playing the position the way he worked so hard to build up throughout the spring and the summer. Getting him back into kind of the mandatory nature of certain things from a fundamental standpoint, that will only help him perform at a high level. So I think it's gonna be more about the physical side of his lower-body mechanics and then just trying to put together a game plan for him throughout the practices of how much can he do, what's the soreness level coming out of practices, to try to be able to have most consistent level of a ramp-up we can with him."

The Vikings' quarterback situation will be a story to keep a close eye on as we get into next week. It feels like O'Connell might not have any desire to name his starter until after he watches McCarthy over the full week of practice.

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