FOXBOROUGH, Mass. - Monday evening will be remembered for the quarterback who failed to finish the game, because it is Michael Vick's health that is the overbearing cloud on the Eagles' prospects this season.

But there can at least be satisfaction from the quarterback who replaced Vick. Because Nick Foles, the rookie third-round pick, continued a scorching summer in which he often plays the position with a prowess that suggests the Eagles have a prospect with enough promise to develop into a reliable player.

Foles finished 18 of 28 for 217 yards for two touchdowns and one interception in the Eagles' 27-17 win over the Patriots. Coach Andy Reid did not yet want to anoint Foles as the No. 2 quarterback this season, but the way he has played makes it a conceivable argument.

"I credit the kid," Reid said. "He's a young guy, and you can see him progress and get better every opportunity he has."

Reid could not remember a rookie quarterback playing as well in his first preseason as Foles. Foles arrived at training camp as the Eagles' third-string quarterback, a raw rookie who offered good size and a good arm but not enough certainty to be among the elite quarterbacks in the draft.

Suddenly, in the first quarter of Monday's preseason game against the Patriots, Foles was behind center playing with the Eagles' first-team offense. The ascension came because of injuries - Vick left the game with a rib injury, and backup Mike Kafka didn't play because of a fractured left hand - but Foles was offered an ample chance to prove his value one week after he drew headlines in the Eagles' preseason opener.

What resulted was an encouraging evening from Foles, whose arm appeared as strong as suggested and who displayed a sense of confidence that belies someone in the situation he entered. It was not entirely praiseworthy, yet it was enough to at least provide reason to smile among the gloom of Vick's injury.

"It's really just staying true to who I am," Foles said. "I'm staying calm and playing ball. Playing with confidence. As a quarterback, you have to play with confidence because the guys around you look to you in crisis."

Foles needed to take command of a veteran huddle when he relieved Vick during the Eagles' second drive. He didn't offer a movie script speech. He gave the play, looked at his teammates and said, "Alright, let's go." Foles completed only one of his first three passes, which might have prompted worry that the way he played in the preseason opener (6 for 10, 140 yards, two touchdowns) was merely taking advantage of the Steelers' deep reserves.

But Foles quickly found his footing. After the Eagles' defense forced one of its two second-quarter turnovers, Foles completed consecutive passes to give the Eagles a lead. His best drive came at the start of the second half, when Foles went 5 for 6 for 87 yards and a touchdown, with the highlight a 40-yard deep pass to DeSean Jackson in which Foles' arm strength was especially apparent.

One criticism of Foles before the draft was his perceived slow feet. At 6-foot-6 and 243 pounds, Foles will never be typecast as a mobile quarterback. Yet he consistently bought time to make a throw and even displayed athleticism on a 24-yard scamper to put the Eagles in field goal range at the end of the first half.

The night was not flawless. One play after the rush, Foles thought he found Jeremy Maclin on a deep pass near the end zone. The rookie failed to identify the safety help, and Nate Ebner jumped in front of Maclin to intercept Foles' pass and keep the Eagles off the scoreboard.

Reid said the complexity of college defenses has helped Foles with the transition. College defenses have improved since Reid started as coach of the Eagles, so someone such as Foles was exposed to more than Donovan McNabb, who arrived in Philadelphia as a first-round pick in 1999, and other rookies who have been in the Eagles' system.

"I think he was better prepared coming [in]," Reid said, "and he's a smart kid on top of that."

The Patriots' defense did not include their top players, so it would be premature to expect Foles to have this type of performance against a starting-caliber defense. But the Eagles made a deliberate choice in the offseason to not sign a backup quarterback with a higher profile and instead let Kafka and Foles be the primary challengers to serve as Vick's No. 2. That's an important position considering Vick's injury history, and the Eagles have witnessed Vick's vulnerability in consecutive games. In both of those games, Foles gave the Eagles reason to be confident that he might be able to become the backup.

"There's still a lot of learning to do, but if that does happen, I'd be like tonight and feel confident in myself," Foles said. "You never want those things to happen. But you got a lot of guys out there who depend on a quarterback to step up."

Contact Zach Berman at zberman@phillynews.com. Follow @ZBerm on Twitter.