When the Giants’ general manager, Ernie Accorsi, and coach, Tom Coughlin, engineered a blockbuster draft-day trade in 2004 to acquire first overall pick Eli Manning, they made the kind of bold move that sometimes leads a team to a Super Bowl — and sometimes leads to disaster. This is the year the Giants need Manning to show how far he’s capable of leading them.

After struggling through a difficult rookie campaign in 2004, Manning started 2005 hot. Halfway through the season, he had 14 touchdown passes and only five interceptions. But he cooled off considerably in the second half of the season.The rest of the year, counting the Giants’ playoff loss to the Carolina Panthers, he threw 10 touchdowns and 15 interceptions. His season ended with that miserable 113-yard, three-interception playoff performance.

The conventional wisdom around the NFL sounds good for Manning: Many coaches say quarterbacks make their biggest leap forward between their second and third seasons because that is the time when they have figured out how to play against the more complex NFL defenses. But an examination of the other quarterbacks who have been selected first overall in the last 20 years shows that they make only modest gains between their second and third years. Those nine quarterbacks — Carson Palmer, David Carr, Michael Vick, Tim Couch, Peyton Manning, Drew Bledsoe, Jeff George, Troy Aikman, and Vinny Testaverde — averaged almost exactly the same number of completions, attempts and yards in their third season as in their second. The young quarterbacks did make strides in getting the ball into the end zone and avoiding turnovers, but only by small margins: The nine quarterbacks averaged 15 touchdowns and 17 interceptions in their second years, compared with 17 touchdowns and 14 interceptions in their third years.

For Manning to improve more than his predecessors have, he’ll need to stop relying so heavily on his favorite receiver, Plaxico Burress. Last year he threw 166 passes to Burress, by far the most of any receiver on the team, but Burress caught only 46% of them. Part of that is Burress’s fault — he’s the type of receiver who makes a spectacular catch on one play and then misses an easy one on the next — but it’s mostly because Manning too often throws to Burress in coverage rather than looking for another option. The best-case scenario for the Giants is that Manning develops a rapport with rookie receiver Sinorice Moss and begins throwing more balls in Moss’s direction and generally spreading his passes around instead of always looking to Plaxico first. However, a thigh injury has prevented Moss from practicing this summer and developing that rapport with Manning.

The Giants hope the development of Moss can offset the decline of Amani Toomer, who will turn 32 this week. Toomer has lost so much speed that the Giants now take the unusual approach of using their tight end, Jeremy Shockey, as a deep threat and using Toomer as a possession receiver. Shockey averaged 13.7 yards a catch last year, more than two yards better than Toomer’s average of 11.4. But Toomer caught a slightly higher percentage of the passes thrown his way, 55% to 53%.

At age 31, running back Tiki Barber still looks fresh despite carrying the ball a career-high 357 times last season. Because he’s a relatively small 5-foot-10 and 205 pounds, Barber has often been relieved of short-yardage duties, and the decreased pounding has helped lengthen Barber’s career. A few years ago the 245-pound Ron Dayne took Barber’s place in short-yardage situations, and last year 264-pound Brandon Jacobs did. The Giants plan to use Jacobs in the same capacity this year. Running behind a good line that has all five starters back, Barber should have another strong season.

Barber’s ability to play at a high level at 31 is impressive, but the high-quality play of defensive end Michael Strahan, who will turn 35 this season, is remarkable. Strahan, who had 11.5 sacks last year, leads an embarrassment of riches at defensive end. Osi Umenyiora had 14.5 sacks last season, and the Giants have two very promising young ends in second-year player Justin Tuck and this year’s firstround draft choice, Mathias Kiwanuka.

With middle linebacker Antonio Pierce quietly having one of the best seasons of any linebacker in the league, the Giants had a good run defense for much of last year. But it fell apart in January after Pierce and fellow starting linebacker Carlos Emmons got hurt. After seeing how a lack of depth at linebacker weakened the defense in the playoffs, the Giants made improving that unit an off-season priority. Free agent linebacker LaVar Arrington is an athletic player, but he has a reputation for losing focus during games, and he has a long history of nagging knee injuries. Rookie linebacker Gerris Wilkinson, a tall and quick third-round pick from Georgia Tech, needs to be ready to play immediately because Emmons has been hampered by a neck injury.

The Giants’ most surprising roster move last week was cutting defensive back Curtis Deloatch, a third-year player who started 14 games last year. That completed a radical overhaul of the secondary, where strong safety Gibril Wilson is the only returning starter from last season. The Giants added two free agent starters, free safety Will Demps from the Baltimore Ravens and cornerback Sam Madison from the Miami Dolphins. The other starting spot will go to second-year player Corey Webster, a very good athlete who made some mistakes last season — the kind of mistakes that, the Giants hope, he can learn to avoid by watching the veteran Madison.

The Giants might have raised some expectations by finishing the preseason 4–0, but their difficult schedule makes them unlikely to match – let alone improve upon — last year’s 11–5 record. The teams the Giants will play this season had a winning percentage of 54.3% last year, giving the Giants the hardest schedule in the league. That means the Giants most likely won’t repeat as division champions — unless Manning can make a big step forward.

Mr. Smith is a contributing editor for FootballOutsiders.com.