The San Diego Chargers fired the proverbial starter's pistol to ignite the sweepstakes to land receiver Vincent Jackson on Monday when they decided against making him one of the record 21 players to receive the franchise designation by the league's 3 p.m. deadline.

Vincent Jackson caught seven passes for 165 yards against the Bears in their game last season. Dennis Wierzbicki/US PRESSWIRE

Believed to be one of the teams expected to make a run at Jackson, the Chicago Bears certainly aren't complaining. But they'd better be preparing their best offer for Jackson because there's sure to be competition for his services from a variety of clubs, including the Chargers, which continue to negotiate with representatives for the receiver on a long-term contract.

By standing idle as the franchise-tag deadline passed, the Chargers opened the door for Jackson to negotiate and sign with another team when free agency begins on March 13 (many times, deals are consummated before the official start of free agency). Jackson wants to remain in San Diego, and it's believed he'll accept a lesser deal to stay with the club. But it became virtually impossible for the Chargers to franchise Jackson under the new CBA regulations.

Jackson earned $11.4 million as the Chargers' franchise player in 2011. To retain Jackson again in that capacity in 2012, San Diego would have been required to pay the receiver 120 percent of his '11 salary, which all would count against the team's salary cap for the upcoming season.

"We discussed it again this morning, and nothing changed. We did not like the franchise number ($13.7 million), never did," Chargers general manager A.J. Smith said in a statement. "Vincent will enter the market, and we will see what happens. We would like to have him continue on with us, but other teams now will enter the picture."

Two NFC North teams -- the Bears and Minnesota Vikings -- are expected to vie for Jackson, along with a host of other clubs including Carolina, San Francisco, Tampa Bay and Washington. The Vikings actually attempted to land Jackson in 2010 through a trade, and it's likely their interest in the receiver hasn't cooled; especially given its situation at quarterback with inexperienced Christian Ponder, who needs more weapons.

Jackson finished last season with 60 catches for 1,106 yards and nine touchdowns, including a seven-catch, 165-yard outing against the Bears on Nov. 20. At the Senior Bowl, a source close to Jackson -- pessimistic about his prospects for remaining in San Diego -- said the receiver hoped the Bears would express interest in free agency.

The question now seems to be what it would take for a team financially to acquire Jackson. Several agents for receivers around the league believe Jackson's reps -- who couldn't be reached for comment -- are seeking upwards of $13 million per year. Those same agents don't expect the market for Jackson to bear more than $12 to $12.5 million per year, although one cautioned that "all it takes is one team."

New Bears general manager Phil Emery was believed to be interested in Kansas City's Dwayne Bowe -- in part, because of their history together -- but the Chiefs took him off the market Monday by designating him their franchise player. Two other receivers -- New England's Wes Welker and Buffalo's Steve Johnson -- came off the market earlier in the day. The Patriots tagged Welker as their franchise player, and the Bills signed Johnson to a five-year extension.

So while the market at receiver thinned out somewhat on Monday, the biggest target -- Jackson -- remains a possibility for the Bears. The club hasn't stated its intentions publicly, but multiple sources believe the Bears plan to make a legitimate run at the receiver.

Should they fail to land Jackson, several competent options at receiver are expected to be on the market next week, including New Orleans' Marques Colston and Robert Meachem, Dallas' Laurent Robinson, Washington's Donte' Stallworth and Reggie Wayne and Indianapolis' Pierre Garcon.