WHEN JEREMY Maclin tore his ACL Saturday, Riley Cooper said he was so upset he almost cried.

"Jeremy's one of my really, really good friends," the fourth-year wide receiver said. "He's a great player. For this to happen to him, I feel for him. I almost shed a tear for him out there on the practice field when I saw him go down."

Losing Maclin, who has averaged 65 catches, 863 yards and seven touchdowns a season since the Eagles selected him with the 19th overall pick in the 2009 draft, is a serious blow to the Eagles' offense.

But injuries are a fact of life in the National Football League. There is a popular saying in the game: next man up. When a starter goes down, somebody else has to step in and replace him.

Cooper is the next man up. Maclin is out for the season and Cooper will get first crack at replacing him. One's man's misfortune is another man's golden opportunity.

"It's an opportunity for everybody," he said yesterday after the Eagles' first practice in pads, at Lincoln Financial Field. "He's out, so we'll see how it goes.

"This is my fourth year. Last year, I started five games. I just want to pick up where I left off last year. I felt like I had my best year yet. I've just got to keep it going. But I feel pretty comfortable, I really do."

Cooper, a 2010 fifth-round pick out of the University of Florida, missed the first five games last season after breaking his collarbone in training camp. Activated in Week 6, he played mainly on special teams and in four-wide receiver sets his first six games back.

But after DeSean Jackson fractured his ribs in Week 12, Cooper replaced him and started the final five games.

The 6-3 1/2, 222-pounder finished with a career-high 23 catches and tied for the team lead in red-zone touchdowns with Maclin and running back LeSean McCoy (three). He had just two dropped passes.

For the moment, the Eagles appear content to go with the players they currently have on their roster and not bring in a veteran free agent receiver to replace Maclin. That could change, but right now, that's the way they're leaning.

"We're always going to explore options and see if there are ways to improve our roster," general manager Howie Roseman said. "But right now, we're excited about some of the young guys we have. And we'll go from there."

An offense that already looked like it was going to be tight end- and running back-centric, almost certainly will be that now that Maclin is out.

That said, the Eagles still are going to need a significant contribution from their wide receivers.

Jackson, who was one of the league's most dangerous wideouts his first 2 1/2 years in the league, has underachieved the last 2 1/2. He has just five 100-yard games and eight touchdowns in his last 34 starts, and his yards-per-catch average has dropped significantly.

The Eagles acquired Arrelious Benn, a former second-round pick of the Bucs, in March. But he has had major problems staying healthy. He injured his knee in the team's first full-squad workout on Friday and is out indefinitely.

Second-year man Damaris Johnson showed some promise last season, catching 19 passes and averaging 13.5 yards per catch as a rookie. But he's just 5-8. Given the need for wide receivers to be able to block in Chip Kelly's offense, you really don't want Johnson and the 5-9 Jackson on the field together a lot.

"But the flip side," Roseman said, "is you've got two explosive guys. You're trying to get as many playmakers on the field as possible. If that personnel grouping [Jackson and Johnson] is what ends up making the most sense, we wouldn't have any reservations about using it in certain games against certain teams."

The best solution, of course, would be for Cooper to step in and play well. He was running with the first-team offense yesterday. But it's still early.

"I don't think it matters right now who's 1 or who's 2," Roseman said. "It's about evaluating all of those guys.

"When you talk about Riley, he's got a lot of great traits. He's big. He's strong. He can go up and get the football. He can block. For a big guy, he can drop his weight and run routes.

"He was hurt by the 2011 lockout. Last year, he broke his collarbone and didn't have a chance to really have a training camp and offseason where he could fully develop and put that to use. We're excited about his potential.

"It's up to him."

Maclin's injury came at the worst possible time for him personally. He's in his contract year. His knee injury is going to severely damage his bargaining position with both the Eagles and other potential suitors.

Cooper also is in his contract year. If he can capitalize on this opportunity, it could be worth millions to him, and he knows it.

"I've just got to play Riley Cooper's game," he said. "I'm not Jeremy Maclin by any means. We have different styles of play. Am I confident in my game? Absolutely. I felt last year, with those last five, six games, I was targeted three times in the red zone and had three touchdowns. I felt like I had a pretty good end of the year. I want to play that same way hopefully through the end of the season."

Cooper is a good fit for Kelly's offense, He's a big target with dependable hands and 4.5 speed. And he is the best blocking wideout on the roster.

"That's perfect for me," he said of the increased blocking responsibilities. "I love that. Six-four, 230. You better be able to block [when you're that size]. That's one of my strengths and I love doing it."

That's the kind of attitude you want from the next man up.

Email: pdomo@aol.com

On Twitter: @Pdomo

Blog: ph.ly/Eagletarian.com