Chemistry on defense. Ends Michael McCrary (knee) and Tony Weaver (ankle), outside linebacker Peter Boulware (ankle), cornerback Gary Baxter (hamstring) and safety Will Demps (elbow) have been injured this preseason. Demps is expected to miss the first month, and the others could be limited in that same time frame. Much of the new 3-4 defense depends on communication, and these injuries may have slowed the growth of this overhauled lineup.
Unit on the hot seat
Secondary. The Ravens will go with three first-year starters in the secondary - cornerback Gary Baxter and safeties Ed Reed and Anthony Mitchell - which means opposing quarterbacks will be licking their chops. Baxter, who worked last year as a backup safety, did not play a down of cornerback in the preseason because of a hamstring injury. And Mitchell is biding his time with the first team again while Will Demps recovers from a dislocated elbow. The only proven commodity is cornerback Chris McAlister.
Unit that will dominate
Linebackers. The Ravens have power on the inside with Ray Lewis and Ed Hartwell and tremendous speed on the edges with Peter Boulware and Shannon Taylor. Lewis and Boulware remain the backbone of this defense, and Hartwell has the look of a budding playmaker. Taylor, another speed rusher, will likely share the strong-side job with Cornell Brown, a thumping run stopper.
Unit that could overachieve
Defensive line. None of the starters weighs in over 310 pounds, which means this group has the potential to wear down. But everyone on this front plays with a high motor, taking a cue from end Michael McCrary. At nose tackle, Kelly Gregg can be effective working inside with leverage. On the ends, McCrary, Tony Weaver and Adalius Thomas could be a formidable rotation.
Unit that could be unpredictable
Receivers. This group has the potential to break through or collapse. Travis Taylor needs to show up every game and Brandon Stokley needs to show he can be healthy for every game. With Chris Redman more effective in the short passing game, these receivers have to be physical enough to get separation off the line and quick enough to elude tackles.
Biggest shoes to fill
Return specialist. Lost in the expansion draft, Jermaine Lewis was one Raven who could change a game's momentum on a single play. The Ravens are attempting to fill that hole with Lamont Brightful, a sixth-round draft pick who has explosiveness but lacks Lewis' instincts as a rookie. There is a strong possibility, however, that Brightful won't be active on game days, leaving Chris McAlister to return punts and Javin Hunter to return kickoffs.
Tight end Todd Heap. He has great hands, size and speed. But to truly appreciate Heap, just watch him catch a short pass over the middle, break a tackle and then explode for a 20-yard gain. The Ravens' best mismatch in the passing game, Heap has developed a rapport with Chris Redman and should end up as the team's top receiver this season. He also has made strides in his run blocking.
Breakout draft pick
Punter Dave Zastudil. It's questionable whether a punter merited a fourth-round pick, but the rookie will have the chance to prove the critics wrong. With an offense that could frequently stall, Zastudil could play a big factor in the Ravens winning the field-position battle.
Favorable schedule. Based on their opponents' records from last year, the Ravens' schedule ranks as the league's sixth easiest. Their opponents had a combined winning percentage of .475 last season. There's only four games against teams that made the playoffs last year. But Cleveland, Indianapolis and Tennessee are expected to rebound from losing seasons.
Youth. Thirty-five percent of the Ravens' roster is rookies. Half of their starting lineup on offense and defense is first-year starters. While young players provide energy, they can also provide mistakes at crucial times. There's a concern that they will all hit the wall at the same time, tiring out some time in the second half of the season.,