PHILADELPHIA — Eagles starters already have missed 20 games this season, and that number is going to keep growing.

Linebacker DeMeco Ryans, the team’s defensive leader, suffered a season-ending Achilles injury in the fourth quarter of the Eagles’ 31-21 win over the Houston Texans on Sunday.

Earlier in the game, starting quarterback Nick Foles broke his collarbone when he was driven to the ground by Texans linebacker Whitney Mercilus. Foles will be out at least five weeks and could miss eight weeks. As long as he can be back in time for the playoffs, the team isn’t expected to put him on injured reserve.

Right guard Todd Herremans also might miss Monday night’s game against Carolina. He played Sunday with a partially torn bicep in his left arm, and left the game in the second half with what the team called an ankle injury. He was replaced by backup Andrew Gardner.

Foles was replaced by Mark Sanchez, who completed 15 of 22 passes and threw for two touchdowns. He also had two interceptions, but one of them clanged off the hands of rookie wide receiver Josh Huff, and the other was mostly a result of a bad route by a couple of his receivers.

Sanchez will make his first start as an Eagle Monday night against Carolina and his first NFL start since 2012.

“I feel great about Mark,” said coach Chip Kelly. “I always said we needed two quarterbacks, and had a chance to get him in here (during the offseason). I thought he’s done a great job in our system. I thought he played outstanding in the preseason and showed no rust or anything when he got in there against Houston yesterday.”

NOTES, QUOTES

–When the cart came out onto the field Sunday for injured linebacker DeMeco Ryans after he suffered a season-ending Achilles injury, all of the Eagles players poured out onto the field and surrounded their defensive leader. “You know, everybody knows it,” coach Chip Kelly said. “You know what DeMeco means to this team. He’s a true leader. We talk about it all the time. He’s Mufasa. You know, he’s our guy. When a warrior goes down, you pick up his shield and go play in honor of him. And I think that’s what our guys did.”

–After Houston got within three points early in the fourth quarter Sunday on a seven-yard touchdown pass from Ryan Fitzpatrick to De’Andre Hopkins, the Eagles put together a 16-play, 80-yard touchdown drive that ate eight minutes off the clock. It was the Eagles’ longest possession of the season. “We’ve talked about how when you’re a good football team, you have to be a good four-minute football team,” Kelly said. “I thought we did a great job of not only taking a lot of time off the clock, but coming away with a touchdown to make it a two-score game. The whole drive just told you a little bit about how we’re coming together a little bit offensively. I think it bodes well for the future.”

REPORT CARD V. TEXANS

–RUSHING OFFENSE: A-plus — The Eagles rushed for 190 yards, 124 in the second half when they wore the Texans down and averaged 5.4 yards per carry. LeSean McCoy notched his second 100-rushing performance in the last three games. McCoy, who averaged just 2.7 yards per carry in the first four games, has averaged 4.8 in the last four.

–PASSING OFFENSE: B — Nick Foles and Mark Sanchez collectively completed 71 percent of their passes and averaged 9.3 yards per attempt, but had three interceptions, though one of them clanged off the hands of rookie wide receiver Josh Huff. Jeremy Maclin had his second straight 150-plus-yard, two-touchdown performance.

–RUN DEFENSE: B-plus — The Texans’ Arian Foster entered the game as one of the hottest running backs in the league, but the Eagles held him to 56 yards on 15 carries before he exited late in the third quarter with a groin injury. The Eagles have allowed just 3.7 yards per carry over the last three games.

–PASS DEFENSE: B — The Eagles, who have been giving up too many long pass plays, gave up two more Sunday. Foster burned Connor Barwin on a wheel route that he turned into a 56-yard touchdown catch and run, and DeAndre Hopkins had a 45-yard completion on an Eagles blitz and beat safety Earl Wolf for a seven-yard touchdown. But for the second straight week, the Eagles held an opposing QB to a sub-50 completion percentage.

–SPECIAL TEAMS: A — Cody Parkey had a 45-yard field goal and had three touchbacks on five kickoffs. Darren Sproles had an 18-yard punt return and the coverage units shut down the Texans’ return game. Donnie Jones put two of his three punts inside the 20.

–COACHING: A-plus — Chip Kelly wore the Texans down with tempo, running 43 plays in the first half and 79 overall. The Eagles averaged a play every 22.0 seconds in the first half. Kelly went for it twice on fourth-and-one and was successful both times.