Two of the Eagles most important offensive players exited Friday's practice early with injuries after borderline dirty hits by two rookie defenders.

Wide Receiver Jordan Matthews attempted to catch a pass along the sideline during full-team drills late in Friday's session.

Earlier, tight end Zach Ertz went to make a reception and rookie defensive back Blake Countess went somewhat low on the tight end.

According to the story, Matthews stayed down for several seconds before heading back inside with trainers with a noticeable limp in his step. Eagles head coach Doug Pederson said after practice that Ertz was undergoing evaluation for a concussion.

Matt Rourke AP: "The tight end (Eagles TE Zach Ertz) is going to catch a bunch of passes this season. I'm not sure for how many yards or how many touchdowns, but he's going to lead the team in receptions."

Ertz was second to Jordan Matthews (85) on the team last year with 75 receptions, which was the 6th-most at his position. He finished as the #10 TE in standard scoring, but was #6 after his Week 8 bye, averaging 6.4 catches for 73 yards and 0.25 TD (on 8.8 targets per game) in his final eight games. Given his size and relative catch radius, his touchdown rate should increase eventually. Playing time was the issue in his first two NFL seasons, but he played 72% of the snaps in 2015 and 79% in his last five games. He’ll be playing in a new offense for a new head coach, Doug Pederson, but Travis Kelce was a key part of the Kansas City offense during Pederson’s tenure.

The Philadelphia Eagles locked down Zach Ertz.

The team announced the tight end inked a five-year contract extension on Monday, keeping him in Philadelphia through 2021.

NFL Media Insider Ian Rapoport reported that the extension is worth $42.5 million, with $20 million in guarantees, which makes Ertz the fourth-highest paid tight end in average and guaranteed money, per a source. Jimmy Graham ($10 million), Julius Thomas ($9.2 million) and Rob Gronkowski ($9 million) are the top three in average per year.

Ertz finished as the #10 TE in standard scoring, but was #6 after his Week 8 bye, averaging 6.4 catches for 73 yards and 0.25 TD (on 8.8 targets per game) in his final eight games. On the season, he racked up 75 catches for 853 yards and two scores. Given his size and relative catch radius, his touchdown rate should increase eventually. Playing time was the issue in his first two NFL seasons, but he played 72% of the snaps in 2015 and 79% in his last five games.