Sources: Jackson, McNeill to hold out

San Diego's Pro Bowl left tackle Marcus McNeill and wide receiver Vincent Jackson are ready to play hard ball with the San Diego Chargers.

After San Diego's front office sent the players letters informing them that their salaries would be cut if they didn't sign their tenders by next week, the players have plotted out a game plan of their own.

Not only will McNeill and Jackson not sign the current or reduced tender, they do not plan to report for the start of training camp and quite possibly well beyond, according to league sources.

Each player wants a long-term deal befitting the salaries of some of the top players at the position. Neither plans to sign his tender anytime soon.

And now, San Diego has a potential major issue looming over the start of its season -- the fact that its Pro Bowl left tackle and Pro Bowl wide receiver cannot be counted on to play.

To protect themselves against a possible holdout from McNeill, the Chargers agreed to a one-year deal with veteran left tackle Tra Thomas on Wednesday.

A three-time Pro Bowl player with the Philadelphia Eagles, Thomas, 35, spent last season with the Jacksonville Jaguars. He has started 168 of 174 games during his career.

Earlier this week, San Diego's front office sent the players letters warning them that if they did not sign their restricted free agent tenders by June 15, McNeill's salary would be slashed from $3.168 million to $583,000 and Jackson's salary would be dropped from $3.268 million to $600,000.

But the players wouldn't sign the existing tender, the reduced tender or even an increased tender. They are steadfast in their wishes for a long-term deal -- as steadfast as San Diego is to get the players to sign the tenders.

It sets up a potential battle between the two sides in which tensions are bound to escalate before they will subside.

When contacted by the San Diego Union-Tribune, which also reported the players' willingness to hold out, Chargers general manager A.J. Smith declined comment.

"I've already addressed the subject in detail and have nothing more to add," Smith told the Union-Tribune.

Now San Diego might have to make plans to move on without either player.

The 26-year-old McNeill is a two-time Pro Bowl left tackle, in charge of protecting quarterback Philip Rivers' blindside.

The 27-year-old Jackson has had two straight seasons in which he has had over 1,000 receiving yards and has led the league in each of those years in average yards per catch.

Neither might be spotted around the Chargers complex for a while. The game before the games is on.

Adam Schefter is ESPN's NFL Insider. ESPN.com's John Clayton contributed to this report.