In the NFL's age of the salary cap, every action elicits a corresponding reaction, and every move results in a countermove.
So, with four quarterbacks selected in the first round of the draft Saturday, what are the ramifications for the incumbent starters with those teams?
San Diego: Even with the respect the staff possesses for Philip Rivers, a player that the Chargers coached in the Senior Bowl and who rated very close to Eli Manning on their draft board, it is uncertain that the North Carolina State star will step immediately into the lineup.
Had the Chargers retained Manning, there is a good chance San Diego would have cleared the way for him to start by dealing incumbent Drew Brees. The likelihood now is that the Chargers will keep Brees, who struggled in 2003, temporarily losing his job to Doug Flutie. Fourth-year veteran Brees has a palatable base salary of $1.56 million and a cap charge of just $2.367 million.
It won't be surprising, though, that if the Chargers sputter, Rivers will take over the No. 1 spot on the depth chart at some point in his rookie campaign.
New York Giants: It will probably be difficult for Kerry Collins, who led the Giants to a Super Bowl berth just four years ago, to serve as the mentor to Manning. It might be just as difficult for New York to keep Manning on the bench. Clearly, the expectation is that he will play quickly.
Collins is in the final year of his contract and, because of that, there is no "acceleration" if the Giants trade or release him. His cap number, $8.95 million, will be exorbitant if he is not the starter, and New York can recoup $7 million in cap room by releasing Collins or trading him.
The big question: Can the Giants find a team interested in acquiring Collins?
Pittsburgh: The selection of Ben Roethlisberger, by a franchise that hadn't exercised a first-round pick on a quarterback since 1980, is almost certainly made for the long-term. The Steelers, who floundered to 6-10 in 2003, don't plan to be selecting as high as the 11th overall pick again any time soon. That said, it was time for Pittsburgh to begin to internally develop a home-grown quarterback.
Incumbent Tommy Maddox, some Pittsburgh insiders had hinted, might have been traded if the Steelers had acquired Rivers, who is more ready to play than is Roethlisberger. The Steelers also have Charlie Batch as an experienced backup. So if Maddox is retained, this will essentially be a "redshirt" season for Roethlisberger.
But there is this angle: Maddox is miffed about his 2004 base salary, just $750,000, and has made it clear he wants his situation revisited. That could be tough, because Maddox now has precious little leverage since he is probably a short-timer.
Buffalo: This could be the most intriguing of the quarterback selections in the first round, since it could signal the eventual end to Drew Bledsoe's tenure with the Bills. The club sacrificed its first-round pick in 2005 to move up and snatch J.P. Losman of Tulane, a guy overshadowed by the "Big Three" quarterbacks in this draft, but a better athlete than any of the others.
A Southern California kid who played in New Orleans, the confident Losman might have to invest in some long-johns to get through the Buffalo winter.
Bledsoe is due a $7 million bonus by Nov. 1 to trigger the 2005-2007 segment of his deal. If the Bills decline to pay that option bonus, Bledsoe could become a free agent at the end of this season. Given the manner in which he regressed in 2003, Bledsoe might be considered overpaid this year, when he is slated to earn a $5.9 million base salary.
Buffalo officials spoke with Bledsoe's agent on Friday about reworking his contract, but there was no progress. This could well be Bledsoe's swan song year with the Bills.
Len Pasquarelli is a senior writer for ESPN.com.