In an ideal world, every general manager would love to trade back a few spots, draft the player who fits a need and gain an extra draft choice or two.
That said, draft trades aren't ideal. They are calculated risks. By Wednesday and Thursday prior to the draft, most clubs go through the laborious process of "stacking their board." Final grades are given to each player after long readings, presentations and debates. Thanks to computers, the stacking process can be done quickly.
The draft order goes from best player to worst. That's the easy part. The hard part is doing the guesswork to determine where other teams rate players and how their needs dictate their selection.
That requires phone work. Fortunately, it's hard to keep a secret in the league. Rumors spread daily like wildfires. Sorting through the information is the most difficult part.
General managers look for telling signs from recent roster moves to find clues, but even those can be deceiving.
Take the Chargers' plight at the top of the draft as an example. While they probably won't end up passing up the chance to draft Eli Manning, they would love to trade down and pick Philip Rivers. But it's easy to see there are only a couple of teams -- the Arizona Cardinals and the New York Giants -- that would be interested in drafting a quarterback. The other seven teams in the top 10 have their quarterbacks.
New Cardinals coach Dennis Green has said for months he's not interested in using the third pick in the draft on a quarterback. Green has always been a trustworthy guy. The Chargers know that. Heck, he worked a few Chargers television shows for them the past couple of years because he lived in San Diego after leaving the Vikings.
But, in the back of their minds, they have to wonder. What if Green is trying to throw them off?
The bigger concern is the Raiders. No one can figure out Raiders boss Al Davis. Most figure he'll trade down and take wide receiver Roy Williams. He's made several moves that would leave teams to believe he's not taking left tackle Robert Gallery. He's made new financial commitments to left tackle Barry Sims and guards Ron Stone, Brad Badger, Mo Collins and Frank Middleton. Lincoln Kennedy hasn't retired yet. And the Raiders are in serious discussions about acquiring Cowboys guard Larry Allen.
The last thing the Raiders need is an offensive lineman. But no one knows for sure. What if the Raiders can't get the value for their pick? Davis could surprise everyone and take Gallery. So, the Chargers have to factor in that possibility. If they trade back, they have to realize that Gallery could be gone.
One thing they know for sure is there is no way to get Gallery and Rivers unless they can trade back and take Gallery and then use some of the picks they acquired to jump back into the top 10 and get Rivers.
That's too risky of a proposition.
Bill Belichick has always been one of the master deceivers in draft circles. When he was in Cleveland, he would send out smoke signals about players he was interested in drafting and then do the complete opposite. With the help of personnel man Scott Pioli, the Patriots have refined their craft to a science and rank among the best in moving up and moving down.
It's allowed them to come into this draft with seven choices in the first four rounds. For one thing, Belichick is a tireless worker. One draftnik, a person who does draft evaluations not tied to teams, notes he sends e-mails to teams he's friendly with and then tries to see who opens them. To his surprise, the draftnik said Belichick opened and presumably read the e-mail on the eve of the Super Bowl. That's right, the Super Bowl his team was getting ready to win.
Very few teams have the complete luxury of just drafting the best player available. The salary cap prevents teams from just taking the best guy on their board if he doesn't fit a need. That's why running backs and quarterbacks are usually hard to project in rounds because teams loaded with those players will pass.
But acts of deception always throw off the equation. A week ago, for example, Butch Davis jumped on his owner's plane and flew to see quarterbacks Rivers and Ben Roethlisberger. It didn't make sense until you factor the possibility that at No. 7, the Browns may not get any of their three targeted players -- Gallery, safety Sean Taylor or tight end Kellen Winslow.
Davis and owner Randy Lerner said publicly the Browns could take a quarterback with the first pick. Why that would seem preposterous is that the Browns signed Jeff Garcia this offseason.
Teams factored in Davis' trip and figured he was either trying to entice a trade from teams drafting in the teens to trade up for a quarterback or maybe he would be bold enough to get a young quarterback. No one knows for sure.
Two recent rumors drove teams at the top crazy. One involved the Redskins trading up from No. 5 to the Raiders' pick by offering left tackle Chris Samuels, an absolutely preposterous idea. First, it would be a cap disaster because the move of three spots would cause even more pressure on a already bad cap situation in 2006. Second, it would be silly for a team going for a Super Bowl to give up something and get younger at tackle. Third, the Redskins have a left-handed quarterback. Left tackles on their roster have less value.
That story was initiated by people close to Gallery. Still, teams can't dismiss the possibility. Anything can happen even though you can toss the Redskins trade up scenario away.
Another rumor came from the Chargers. General manager A.J. Smith said Friday he talked with Redskins owner Dan Snyder about the first pick in the draft. He didn't say an offer was made. All Smith was doing was confirming that the Redskins and the Giants are the two teams he's talked to about the first pick. The Redskins fired back with angry denials because they are tired of being used in trade discussions.
Perhaps the newest dynamic in trade discussions is the calculated draft chart. Each team has one although some top executives don't go by it. The charts, which actually go back to the days of former coach Tommy Prothro, assing a value to each pick. The top number is usually 3,000. Let's say the seventh pick is worth 1,500. To get fair value, a team would have to give up a high second-round pick worth 700, a third-round pick worth 300 and maybe a high pick from next season to meet the 1,500-point difference.
That works well in some instances but the chart could cause a problem. Every team has a different chart. And when you include a player in the deal, a trade conversion can be stalled. The chart worked well in the Bengals trade with the Broncos that allowed Denver to move from No. 24 to No. 17. The Broncos wanted third-round value for cornerback Deltha O'Neal. To get the numbers right, the Broncos threw in a fourth-round choice. The points worked, and the deal got done.
The point system may delay a possible deal between the 49ers and Eagles. Included in a trade proposal from the Eagles to move from No. 28 to No. 16 is Eagles guard John Welbourn. On some charts, that's a 280-point jump, which would require two Eagle third-rounders or a second-round choice from the Eagles as long as the 49ers give back a fifth.
Until an agreement is made on Welbourn's worth, the deal is stalled. The Eagles would only like to give up Welbourn. The 49ers want an extra draft choice.
As you can see, it's not an ideal world getting draft day trades done.
John Clayton is a senior NFL writer for ESPN.com.