PHILADELPHIA -- The instant euphoria of owning the best record in the National Football League quickly turned to bittersweet reality one day later for the Philadelphia Eagles due to season-ending injuries to two key players.

After improving to 6-1 following a 34-24 victory over the Washington Redskins on Monday, the Eagles were jolted with the news that All-Pro left tackle Jason Peters (MCL and ACL) and linebacker Jordan Hicks (ruptured Achilles tendon) would be lost for the remainder of the season.

The Eagles, who have won five straight, will host the San Francisco 49ers (0-7) on Sunday at Lincoln Financial Field. Only the 49ers and Cleveland Browns remain winless in the NFL.

"This is a resilient group, and we've seen it already in the first two months of the season," Eagles coach Doug Pederson said. "It's a great testament to the guys again (Monday) for battling and finishing the game."

Halapoulivaati Vaitai replaced Peters at left tackle and is likely to start against the 49ers. Meanwhile, look for a group effort in replacing Hicks with Mychal Kendricks, Najee Goode and Joe Walker combining at linebacker.

"Wherever the coaches tell me to go," Vaitai said when asked about his role moving forward. "If they ask me to play center, I will play center. This is my job, and I have to play wherever they want."

Thanks in large part to the stellar play of quarterback Carson Wentz, the Eagles have started 6-1 or better for the ninth time in franchise history. The last time occurred in 2004, when they began 7-0 and advanced to the Super Bowl before losing to the New England Patriots.

Wentz was 17 of 25 for 268 yards and four touchdowns to four different players against Washington. He already has 17 touchdown passes this season, one more than all of last season when the Eagles finished 7-9.

Wentz is the first Eagles quarterback since 1950 to throw 17 or more touchdowns and no more than four interceptions through the first seven games of the season. He is also the youngest quarterback to have those statistics since 23-year-old Dan Marino accomplished the feat in 1984 with 20 touchdowns and four interceptions.

"I just have a ton of confidence in our guys," Wentz said. "That's something that makes, I think, our offense tough to defend, that we have guys everywhere that can step up and make plays.

Regardless of who is healthy, the Eagles will continue to compete. That mantra has been instilled in the team from the first day of training camp.

"Quite honestly, I don't think of necessarily being 6-1," Pederson said. "I think of it as just getting better each week. We have to win each week. We have to be 1-0 each week. That was our challenge this past week and for going into this game. We don't talk about those types of things outside of the building."

The 49ers struggled mightily last Sunday in a 40-10 loss to the Dallas Cowboys. For the most part, the 49ers have been competitive this season, losing five games by three points or fewer.

A mixture of injuries and young players has made the situation quite difficult for coach Kyle Shanahan.

"We're just not trying to win enough games to make it look acceptable," Shanahan said. "We're trying to build an organization, build it from the bottom to the top the right way, so we can have sustainable success."

San Francisco right tackle Trent Brown entered the concussion protocol, and his availability is unknown for Sunday. Linebacker Reuben Foster sustained a rib injury, but X-rays came up negative, and he is expected to the Eagles.

The 49ers feature 32 players who have less than four full seasons in the league, including 15 rookies, according to the San Francisco Chronicle.

Shanahan refuses to make any excuses.

"My first decision is what gives us the best chance to win every Sunday, and that will always be the most important thing to me at the time," Shanahan said. "There's not really a situation on our team where we're just saying, 'Hey, play the young guy because he's younger,' while we have a better player sitting right there on the bench. So, we take all that into account. Yeah, we do have a lot of rookies out there, but it's not just because we're deciding based off age who should play."

Quarterback C.J. Beathard, making his first NFL start Sunday, was 22 of 37 for 235 yards with two lost fumbles against the Cowboys. Beathard was also sacked five times.

After the trip to Philadelphia, San Francisco will return home for three consecutive games against the Arizona Cardinals, the New York Giants and the Seattle Seahawks.