Jamar Chaney remembers April's draft, and the waiting. And waiting. And waiting.

He waited until the seventh and final round, even though he ran the fastest 40-yard dash of any linebacker at the scouting combine.

Chaney has also had to wait for his chance to get on the field with the Eagles' defense, but he will get his opportunity Sunday in some of the most challenging circumstances possible.

He'll make his first start at the heart of the defense against one of the best running-back combinations in the NFL. He'll be making defensive calls on the road against a potent New York Giants offense. And he'll be doing it all in a game critical to the Eagles' playoff hopes.

"The Giants are a good football team and they'll test the linebackers now with that run game, the way the tight end plays, the screen game, and so on," coach Andy Reid said.

Middle linebacker Omar Gaither, who also made his first start late in his rookie year, said he expected the Giants to test Chaney's acumen at making reads and adjustments.

"A guy making his first start ever is going to be, in their eyes, a spot where you attack," said Gaither, who will be Chaney's backup. "I expect that, he expects it, so it's not like it's a surprise."

Drafted 220th overall, the quiet Chaney played almost entirely on special teams until Sunday against the Cowboys, when Stewart Bradley suffered an elbow injury.

"I was disappointed at being a seventh-round pick, but at the same time I came in here with a chip on my shoulder wanting to prove everybody wrong," Chaney said. "A lot of [general managers] passed on me, so I want to make it known that they made a mistake."

Twenty-two linebackers went ahead of him - more, if you count hybrid end/linebacker types such as Ricky Sapp, whom the Eagles took in the fifth round.

Chaney's challenges against the Giants will be both physical and mental.

Start with the physical: Chaney has speed, as evidenced by his 4.54-second time in the 40. But at 6 feet and 242 pounds, he's four inches shorter and 16 pounds lighter than the man he replaces.

He's also four inches and 22 pounds smaller than Giants running back Brandon Jacobs.

"Jacobs, you definitely want to hit him before he gets started," Chaney said. "Once he gets started, it's hard to tackle him."

He also has Ahmad Bradshaw to account for. When these teams met in November, the Eagles held the Giants to 61 rushing yards and a 3.2-yard-per-carry average, both season lows for the Giants. But the Giants have run for 135, 197, and 213 yards in the three weeks since the rivals met in Philadelphia.

Scouts praised Chaney's athleticism as a star at Mississippi State but criticized his play against the run and ability to shed blockers, a problem that plagued fellow linebackers when the Eagles struggled against the run earlier this year.

Reid, however, said Chaney has improved the way he uses his hands - a key aspect to getting off blocks.

As middle linebacker, Chaney will be making play calls and adjustments before the snap. If a tight end goes in motion, he has to relay that to the defensive line. He has to make sure that a blitz comes from the proper side and that the linemen are in the proper gaps.

"He's the quarterback of the front seven," said linebacker Moise Fokou. ". . . You're pretty much talking all the way up until the ball is snapped."

By all accounts from his coaches and teammates, Chaney did well Sunday, stepping in in the second quarter after Bradley was hurt. A 4-3 middle linebacker in college, Chaney said he was used to making play calls.

"He didn't miss a beat as far as calls go," Reid said.

In Chaney's mind, he might have been drafted earlier - no later than the fourth round - and had this shot sooner. He might have gone far earlier in the draft. NFL GMs thought less of him. Who was right? Sunday will help tell, in one of the biggest games of the year.

Contact staff writer Jonathan Tamari at 215-854-5214 or jtamari@phillynews.com. Follow him on Twitter at www.twitter.com/JonathanTamari.