PHILADELPHIA -- Here are five observations on the Philadelphia Eagles, gleaned from their two Monday practices, and discussions with coaches and team officials:

1. A scary thought for the rest of the teams in the NFC East and for the league in general: Queried on the identity of the young veteran who made the biggest jump at training camp head coach Andy Reid cited quarterback Donovan McNabb, who entering his fourth season, already ranks in the minds of most experts as one of the NFL's top players at his position. "Now this will be the last year that we're able to say that about (McNabb)," said Reid. "He's reached a level now where, after this season, his strides will be incremental. It will just be little stuff, the nuance-type stuff, involved with the position." For a player who is just 25 years old, McNabb clearly is the guy from whom everyone in the Eagles locker room takes his cue. He is far more at ease talking about the team than about himself, is impressively articulate in putting things into perspective, yet has a sense of what he means to the franchise. Everything here revolves around McNabb and it's unusual for such a young veteran to command so much respect. Then again, few fourth-year players possess the maturity McNabb has. McNabb made a few eye-opening throws in the morning practice but, truth be told, he has done that for three seasons now. What he still needs to improve upon is making all the throws some folks consider mundane, like the swing pass to the back in the flat, and the short hooks.

2. A series of injuries, particularly the broken foot that could sideline tackle Hollis Thomas for much of the year, has rendered the Eagles defensive line a tad thin. The versatile Brandon Whiting is nursing a hamstring strain but should be ready for the start of the regular season. There's no denying the loss of Thomas, a terrific run-stuffer, is a big one. But don't look for the Eagles to make a move. They didn't panic when Thomas went down and, in fact, refused to be lured into the Sam Adams chase. Second, there likely isn't anyone available in the market right now who is any better than what Philadelphia already has on hand. There aren't many veteran defensive lineman still looking for work. Nor is there apt to be anyone released next week, in the first leaguewide roster cutdown, who could make a difference. The Eagles are leaning on the fact they still have seven veterans who have all lined up and played in the league. Two key youngster to watch: Second-year left end Derrick Burgess and third-year tackle Darwin Walker. The former is likely to supplant Whiting as the starter at left tackle. Burgess passes the eyeball test from an athletic standpoint, is physically cut, and had six sacks as a situational player in his rookie season. Only four rookies in '01 had more sacks than that. Still, Burgess isn't very big (a shortcoming along the Philadelphia defensive front), and will have to anchor against the strongside run. Remember, the weakside end, Hugh Douglas isn't a terror against the run. Walker is an intriguing guy, claimed on waivers from the Arizona Cardinals in 2000, and blessed with deceptive strength and good quickness. He probably won't clog the interior as well as Thomas, and might not be as optimum a complement to fellow tackle Corey Simon, but he was very solid-looking in the Monday morning practice. Simon is an active inside player, perhaps a better player against the pass at this point in his career, and only three defensive tackles in league history have more sacks than Simon's 17 in the first two years of his career. The lowdown on the defensive line: The picture isn't quite as rosy as Eagles officials portray it but neither is it as dire as some suggest. One personal note: Two years ago, while working at another internet site, I predicted that then-Redskins defensive end N.D. Kalu would be a double-digit sack guy. Hey, N.D., time to do something, my man. Honest, I didn't mean double-digit sacks for your career. Kalu is alternating between end and strongside linebacker. He's got 10 ½ sacks in five seasons.

	Levon Kirkland (93) had 101 tackles last season for the Seahawks.

3. We don't know how much tonnage Levon Kirkland has shed since he signed with the Eagles, reportedly weighing in at 304 pounds, but the middle linebacker could turn out to be one of the best $750,000 investments that any team makes this year. During his best years in Pittsburgh, when he checked in at 270-280 pounds, Kirkland could run. The Steelers didn't have to take him off the field on third down and, one of the reasons their defense was so solid was Kirkland's ability to get downfield. He could turn and run down the middle of the zone, cover tight ends in crossing routes and get out in the flat on running backs. OK, so Kirkland probably doesn't run quite that well anymore, true enough. But he flashed some of the old coverage skills on Monday and, the bet here is that Kirkland logs as many snaps this season as Barry Gardner, the man who was to replace the departed Jeremiah Trotter. After all, in his alleged football dotage, Kirkland still had more than 100 tackles in Seattle last season. It might well be a case where coordinator Jim Johnson devises ways to play into the strengths of both Kirkland and Gardner. Such time-sharing arrangements don't always work out for the best, but no one should underestimate Johnson's brilliance in finding ways to use personnel. Wouldn't it have just been easier to retain Trotter, whom the Eagles designated a "franchise" player early in the spring, only to rescind the label, making him a free agent? Maybe, but the team made the decision, and has moved on. Put down Kirkland as a guy who just might have enough juice left in the tank to give Philly one more season at a relatively high level and to provide locker room leadership.

4. It's still a little early to break out the rocking chairs for cornerbacks Troy Vincent (age: 31) and Bobby Taylor (28), and free safety Brian Dawkins (28) figures to be around for a while as well. But the Eagles invested each of their first three draft choices this year on defensive backs -- corners Lito Sheppard (No. 1) and Sheldon Brown (No. 2b) and safety Michael Lewis (No. 2a) -- and the gambit has two-fold implications. First, it's a concession that Philadelphia figures it will again have to go through St. Louis to get to the Super Bowl. Second, in one bounty, the Eagles have replenished an area that had been ignored in the draft. Philadelphia hadn't selected a defensive back since 1999, when it chose safety Damon Moore in the fourth round. It hadn't taken a defensive back in the top three rounds since taking Dawkins in the third stanza in 1996. And the team hasn't had a first-rounder in the secondary since Ben Smith in 1990. So how are the kids doing? Sheppard had a terrific interception in Saturday's preseason loss at New England, the rookie getting position on much bigger Patriots wideout Donald Hayes to make the steal. The former University of Florida standout doesn't quite have the kind of prototype size teams want, but he is very quick, and he showed that in the Monday morning workout. Sheppard could supplant Al Harris, the team's longtime "nickel" corner, in that role. Certainly he brings a big-play mentality to a secondary that already rates as one of the league's most opportunistic units. Lewis suffered a high ankle sprain Saturday, is out for a week or two, but had manifested plenty of toughness before the injury, and Reid feels he will be a special teams standout as a rookie. Brown, another guy who plays bigger than his size, should also play in the kicking game.

5. While the Reid-designed offense spreads the ball around -- better to have four or five players with 50-60 catches apiece, rather than one guy with 100 receptions, and a No. 2 receiver with just 40 catches -- someone still needs to step up into the second spot opposite James Thrash. The feeling is that the reed-thin Todd Pinkston will be that player, with 2001 first-rounder Freddie Mitchell as the slot receiver, while pushing for playing time. Pinkston is an angular player, 6-feet-2 and just 174 pounds, but he has good speed and is a tall target coming across the hashes on crossing routes. The former No. 2 draft choice started quickly in 2001, with 19 catches in the first five games of the year, then hit a lull in the middle part of the schedule before finishing pretty strong. There is no reason, in this offense, Pinkston shouldn't catch 60 or more passes and score 6-8 touchdowns. Both he and Mitchell appear more comfortable this spring.

Len Pasquarelli is a senior NFL writer for ESPN.com.