FOXBOROUGH, Mass. – Whether it's Carson Wentz or Nick Foles, when the Eagles open the season in less than three weeks, their starting quarterback would have likely played less than a half of preseason football.

And that's the best-case scenario.

Wentz, this past week, all but ruled himself out for the entire preseason. And on Thursday night, Foles, who had already missed the preseason opener, suffered a shoulder strain that effectively shut him down at least until the Eagles host the Falcons on Sept. 6.

Does either need to play in the preseason? Not really. Wentz played in just one game before his NFL debut two years ago, and his rookie season turned out just fine. Foles sat out the entire preseason last year, and while he wasn't called upon until Week 8, he would only go on to become Super Bowl MVP.

If Wentz, who's trying to return from reconstructive knee surgery in less than nine months, is cleared by the opener, then Foles' injury becomes just a minor distraction. But if he isn't ready – "It's going to be close," Wentz said Tuesday. – then his backup's recovery becomes the team's second-most asked-about timetable.

"I'll go in tomorrow, get treatment on it, and just go from there," Foles said. "It feels alright, it feels pretty good. Hopefully, there's no issues."

The main argument for slow-playing Wentz's return has always been centered on Foles. Why risk the franchise's future for a game or two when you have the NFL's best No. 2 quarterback in the barn? But if neither has been given the green light by then, Nate Sudfeld suddenly becomes the starter.

The No. 3 quarterback has obvious ability, evident by his performance in the Eagles' 37-20 loss to the Patriots. But he is a long way from Wentz and Foles, and coach Doug Pederson would need to streamline the offense for his third-stringer.

"It's my job to be ready whatever position I'm in," Sudfeld said. "And I have confidence in myself, I have confidence in my teammates."

The Eagles' second preseason game was supposed to be an economical dry run for Foles and the first-team offense and a victory lap against the team he bested in the Super Bowl. He missed last week's exhibition with neck spasms, but had two games – assuming he would rest in the preseason finale – to fine-tune his passing.

But Foles was rusty. He's never been much of a training camp quarterback, often preferring to work on his craft as if he's a veteran pitcher trying out a new grip. But he had been shaky before and after his initial injury and carried that inconsistency into Gillette Stadium.

He completed just 3 of 9 passes for 44 yards and was sacked three times.

"The balls were a little high early," Pederson said. "Just a little accuracy issue."

Foles was shorthanded. Three of his top four receivers – Alshon Jeffery, Nelson Agholor, and Mack Hollins — were sidelined. He did have tight end Zach Ertz and receiver Mike Wallace – both were held out against the Steelers — but the deck wasn't stacked.

The most glaring absence was on Foles' blind side. Jason Peters was rested and Halapoulivaati Vaitai started in his place at left tackle. Vaitai, of course, did yeoman's work stepping in for Peters after he suffered a season-ending torn anterior cruciate ligament last October. But he got roasted by an Adrian Clayborn outside rush and Foles was a sitting duck.

The Patriots defensive end whacked Foles' arm just as he cocked to throw. The ball popped out, and as linebacker Ju'Whaun Bentley ran the other way with the fumble, the quarterback hunched over and grabbed his arm.

Foles winced as he halfheartedly jogged after Bentley, who motored 54 yards for a touchdown. And when he walked to the sideline, the Eagles training staff whisked him into a pop-up medical tent.

The last time an Eagles quarterback walked into that tent on the road, Wentz learned he had torn his ACL and headed indoors at the Los Angeles Coliseum. Foles' night was done – Pederson said he probably would have played one more series if not for the injury – but he stayed on the sidelines and helped Sudfeld the rest of the way.

Foles has a history of arm injuries. As a rookie in 2012, he fractured his right hand. Two years later, he suffered a season-ending broken collarbone in his left shoulder. And last year, Foles missed the entire preseason with what the team termed "elbow soreness," although he would later reveal in his book that he had a partially torn tendon.

He appeared to initially grab his elbow and then his rib area after Clayborn's hit, but the Eagles' initial diagnosis was a shoulder strain. Even if it's mild, the team is unlikely to place him further in harm's way this preseason.

"It's just the shoulder," Foles said. "It just sort of got jarred in a funny way as I was following through."

Sudfeld, who was acquired last year after the preseason, could certainly benefit from more time in Pederson's offense. His numbers against the Patriots were impressive – 22 of 39 for 312 yards and three touchdowns with one interception — as were some of the throws – a 17-yard touchdown pass to tight end Richard Rodgers was a highlight – but most of the 24-year old's snaps came against reserves.

Foles' rematch with the Patriots – if it can be called that – didn't quite live up to the last meeting – if the two can even be compared. He missed receivers, held the ball too long, and wasn't in rhythm.

"It wasn't good," Foles said of his first live football since Super Bowl LII. "But at the end of the day it felt good to be back out there."

The Eagles, though, would have taken an even worse performance in exchange for a healthy exit. They've been playing the waiting game with Wentz for months, and now they have two quarterbacks to monitor with the defense of their title only 20 days away.

Foles did finally receive a post-Super Bowl handshake from Patriots quarterback Tom Brady. All it took was seven months, although Foles said the perceived slight was overblown.

"I've always respected Tom. I've met Tom several times. It was great to see him," Foles said of their post-game handshake. "I think everyone made a bigger deal because at the end of the day he's a great dude."