Nobody really knows for sure in the middle of March how the players signed in the last week will impact the team. That's the crapshoot of free agency. But there are projections to make as head coach Chip Kelly and general manager Howie Roseman configure a roster that looks so dramatically different than it did at the end of the 2012 season.

Eight may not be enough for the Eagles in free agency, but we now have a chance to break down the newcomers with a bit of long-range forecast for their roles as Eagles ...

JAMES CASEY, tight end

Whether he is labeled a tight end or a fullback or an H-back, James Casey is going to be put in position to make some plays. The Eagles really wanted Casey, obviously, and made the strong play to out-recruit more than a dozen teams who were interested in the athletic, hard-working and very productive young player.

Casey isn't here to take Brent Celek's job. He's here, instead, to compliment Celek, maybe open up the outside for DeSean Jackson and Jeremy Maclin, and be the "move" player in the offense that Kelly uses to create favorable matchups.

Whether that means Casey lines up as a tight end, or in the slot, or as a man in motion or in the fullback stance, hey, anything is possible. The idea is to make defenses account for Casey. The hope is that he's too fast for a linebacker in coverage and took big for a safety in space. Casey is 6 feet 3, and he could be a valuable weapon in the red zone.

CONNOR BARWIN, linebacker

Conner Barwin recorded 11 1/2 sacks in 2011 and established himself as a big-time pass-rushing threat off the edge in a 3-4 defense. The Eagles, it is clearly obvious, are going to incorporate a lot of 3-4 into their scheme, and they needed a proven element to get to the pass rusher. Enter Barwin, who saw his sack numbers drop to three in 2012 as the Texans used him in a variety of ways. Barwin played the run well and had 16 quarterback hits and 12 tackles for loss.

Here, it's likely that Barwin would play on the strong side and rush the quarterback off the edge. He's here to add some punch to the pass rush as the Eagles meld some of the talent they used in the 4-3 scheme into Bill Davis' new-look defense. What Barwin's arrival means for the likes of Trent Cole, Brandon Graham and Co. remains to be seen, but it's clear that Barwin is being counted on to bring some fury off the edge.

CARY WILLIAMS, cornerback

A starter for the last two full seasons in Baltimore and an instrumental piece in the Ravens' Super Bowl run in 2012, Cary Williams has an opportunity to hold down a starting job here. The Eagles love the way Williams played in Baltimore with his size, range and toughness. He can play in man-to-man situations and he gets his hands on the football. The Eagles like that he is a good, willing, interested tackler who plays with some swagger.

Williams has the physical tools to match up with the big-time receivers on the Eagles' schedule this season. We don't know if defensive coordinator Bill Davis wants to blitz a lot or if he plays zone schemes in coverage or any of the X's and O's, so that remains to be seen, but understand that Williams is coming here to play a major role at cornerback.

PATRICK CHUNG, safety

Injuries slowed the progress of Patrick Chung in New England and his 2012 campaign was not as productive as he wanted. Chung is reunited with head coach Chip Kelly, who was at Oregon for a couple of seasons during Chung's time there.

Is Chung the rising safety who appeared to be on the verge of some Pro Bowl recognition in his first three seasons with the Patriots or have injuries set him back too far? Chung says he's healthy and ready to go, and he's got an infectious, positive personality that will be great in the locker room.

There is so much still unknown, though, that it's going to e fun to see how the defense shapes up. The Eagles have a lot of new pieces to fit together in the scheme.

BRADLEY FLETCHER, cornerback

The numbers suggest that Bradley Fletcher should have played more in St. Louis. Quarterbacks compiled a passer rating of 55.8 throwing at Fletcher last season, according to *Pro Football Focus. *Yet Fletcher was the fourth cornerback for the Rams. Stange.

Here, Fletcher has a chance to earn significant playing time and perhaps even start. The Eagles may still use a draft pick on a cornerback -- everything appears to be on the table -- or they could add one later in free agency or via a trade. The team wants depth here, big time.

Still in the mix is Brandon Boykin, who impressed in his rookie season. The Eagles also want to look at Curtis Marsh for a third season as well as Brandon Hughes and Trevard Lindley. Chris Hawkins and Eddie Whitley were signed to add some competition in practice and get a chance to earn a roster spot.

KENNY PHILLIPS, safety

A first-round draft pick in 2008, Kenny Phillips has had his career sidelined by a series of knee injuries. He was limited to seven games last season and hasn't played a full year since 2010.

So there's a sizeable injury question here. Phillips has a one-year contract and a chance to earn playing time. He's tall and rangy and talented, and if Phillips had stayed healthy his entire career he would have been one of the best in the game, perhaps.

The Eagles clearly want open roster battles in the secondary and throughout the defense. Phillips is right in the mix with that.

ISAAC SOPOAGA, defensive lineman

Everyone seems to have a good idea of how Isaac Sopoaga fits in. The Eagles are going to have him as a space-eating nose tackle when they have a three-man front and they will use him as a defensive tackle when they are in a four-man look. Sopoaga has to be durable, powerful and quick off the ball. He may not put up a lot of numbers, but his ability to take up blockers will be instrumental.

A solid veteran player who was part of the 49ers' resurgence, Sopoaga has to be strong at the point of attack for this run defense to flow to the football and be successful. He's a high-energy player who has the size and athletic ability to really help out.

JASON PHILLIPS, linebacker

An inside linebacker who has had minimal starting time in the NFL, Jason Phillips may play a more integral role on the special teams initially. Certainly, Phillips will get a chance to earn playing time at linebacker, but he's viewed as one of the key pieces for Dave Fipp's special teams.

Phillips is a hard-playing, physical guy who is just what the Eagles need on special teams if he plays as well as the Eagles think he can.