Merry preseason, everyone. It’s been a long offseason, but football is finally gearing up again and to celebrate I’m rolling out a new series on TSR entitled “2010 NFL Question Marks,” where I discuss one or two of the biggest concerns that teams have heading into the new season. Granted, some teams have more issues than others, but I’ll primarily be focusing on the biggest problem areas. Today I’ll be discussing the lack of depth the Eagles have in their secondary.

Truth be told, the Eagles are in pretty good shape entering the season. The question on everyone’s mind is whether or not Kevin Kolb can replace Donovan McNabb, but I wouldn’t necessarily deem the quarterback position a weakness.

Nor would I say secondary is a weakness either. I like the starting four of Asante Samuel, Ellis Hobbs, Quintin Mikell and highly intriguing rookie Nate Allen. But after trading Sheldon Brown to the Browns in the offseason, the depth behind those players is now where the concern lies.

Hobbs, who keep in mind is coming off neck surgery, is expected to return kickoffs once the regular season starts. If he were to go down with an injury, it would leave the Eagles with Macho Harris, Joselio Hanson or fourth-round pick Trevard Lindley at the cornerback position opposite Samuel. And none of them have proven that they can be starters at this level. (Although to be fair, Lindley is only a rookie.)

And what if Allen struggles as a first-year starter? All indications are that he’s a stud in the making, but the regular season hasn’t started yet and thus, he hasn’t officially been tested. After losing his job to Harris last season and battling injuries throughout the year, can the Eagles get by with Quintin Demps if Allen can’t produce as a rookie?

Of course, most of this is hypothetical, which is why I’ll reiterate that I don’t think the Eagles have any predominant weaknesses. Again, I think their starters are solid and Allen has a legitimate chance of winning the Defensive Rookie of the Year award if he can live up to expectations.

That said, this is still a thin secondary and Andy Reid better hope that this unit can stay healthy throughout the year. An injury to a starter could derail Philly’s chances of returning to the postseason.

Sunday’s Best: Redskins (3-1) at Eagles (2-2) 1:00 PM ET FOX
Who would have thought after four weeks that the Washington Redskins would be right in the thick of things in the NFC East? Especially after they bombed in the opener against the defending Super Bowl champion New York Giants. But they are, and a big reason for that is the maturity of QB Jason Campbell, who has looked comfortable running Jim Zorn’s West Coast Offense the past three weeks. But he’ll get a major test this weekend against Jim Johnson’s blitz-happy defense. The WCO is predicated on short timing routes and getting the ball into the hands of receivers so they can get yards after the catch. If Campbell can’t get the ball out of his hands quickly, Philly is sure to produce plenty of sacks and turnovers. Whether or not the Eagle offense converts those turnovers into points remains to be seen, however. In their loss last week to Chicago, Donovan McNabb struggled getting the Eagles into the end zone without the threat of Brian Westbrook in the backfield. Westbrook will be a game time decision, although he has seen a fair about of practice time this week, which might be a good sign that he’ll play. Expect another physical matchup between NFC East rivals.

Upset Watch: Bills (4-0) at Cardinals (2-2), 4:15 PM ET CBS
I’m not fooling oddsmakers by calling this a potential upset because they’ve already established the Cardinals as 1-point favorites. But considering how well the Bills have played this year and how Arizona surrendered 56 points in last weeks loss to the Jets, a Cardinal victory would be an upset. The fact of the matter is that the Cards just flat out play better in the desert than they do on the road. They’re a completely different team and while dynamic wide out Anquan Boldin is not expected to play after suffering a nasal injury last Sunday, the Cards have more than enough offensive weapons to pull out a win. The key will be Kurt Warner not turning the ball over and for the team to play all four quarters. Buffalo has trailed in the second half of three of their four victories this year, which means that they’ve been outstanding in the clutch. Arizona will have to play a complete game to earn a win, but an upset could be in the making.

Intriguing Matchup: Steelers (3-1) at Jaguars (2-2), 8:15 PM ET NBC
The Steelers may be 3-1, but they can’t feel too good about the way things are unraveling as injuries continue to mount. Not only will Pittsburgh go into this game without their top two backs in Willie Parker and Rashard Mendenhall, but Ben Roethlisberger is also dealing with shoulder and hand injuries and OT Kendall Simmons is now lost for the year. The Steelers had offensive line issues coming into the season with Simmons in their lineup. Now they have to play without him, which isn’t good news for Big Ben and the rest of the offense. The Jaguars started the year 0-2 but are now gaining confidence after beating the Colts and Texans in dramatic fashion over the past two weeks. The running game has opened up the passing attack for David Garrard, who is starting to play like the quarterback who led the Jags deep into the playoffs last season. We’re going to see what Pittsburgh is made of, because Jacksonville is starting to show signs of the Super Bowl contender that everyone that they’d be in preseason.

Other Notable Games:
Titans (4-0) at Ravens (2-1), 1:00 PM ET
Tennessee is one of only two teams still undefeated and perhaps is playing the best defense in the AFC. Rookie Joe Flacco looked like he was starting to come into his home against the Steelers, so it’ll be interesting to see how he fares against a tough Titans’ defense.

Buccaneers (3-1) at Broncos (3-1), 4:05 PM ET
This is one of the best matchups on the Week 5 schedule as it pits Monte Kiffin’s defense against the Broncos’ offense, which has been one of the best units in the league so far. Can Denver bounce back from its embarrassing loss to the Chiefs last week? Can the Bucs further convince people that they’re a contender with Brain Griese under center?

Bengals (0-4) at Cowboys (3-1), 4:15 PM ET CBS
Ocho Cinco vs. Grab Your Popcorn. Should be a good one.