San Diego ? Antonio Gates didn’t meet the San Diego Chargers’ ultimatum to sign a contract by Saturday afternoon, meaning the defending AFC West champions will be without their All-Pro tight end for at least the season opener against Dallas.

In an extreme move to break an impasse in negotiations, the Chargers ordered Gates to report to camp and sign a contract or face a three-game suspension. Gates’ agent and the Chargers continued to negotiate up to the 12:30 p.m. deadline, but again failed to agree on a multiyear deal. Gates has refused to sign the $380,000, one-year contract the team tendered him as an exclusive-rights free agent.

Once Gates does sign a contract, he will be put on the Roster Exempt List, automatically triggering the suspension, the team said in a statement. He will miss the team’s final two exhibition games, at Minnesota on Friday and San Francisco on Sept. 1 at home, as well as the season opener against the Cowboys on Sept. 11 at Qualcomm Stadium. If he doesn’t sign by Thursday, he’ll also miss the Sept. 18 game at Denver.

Gates, agent Andre Colona and general manager A.J. Smith didn’t return calls seeking comment.

“Obviously, if Gates turns out missing the first game because of this, that’s disappointing for everyone in this locker room because he is big part of our team, and we don’t want to see that happen,” quarterback Drew Brees said after practice Saturday, but before the deadline passed.

“He’s someone we need on the team, but business is business,” said running back LaDainian Tomlinson, who missed most of his rookie training camp in 2001 in a contract holdout.

Tomlinson said he spoke with Gates by phone Friday night.

“He was hoping things got worked out. Hopefully things still get worked out,” Tomlinson said. “We obviously need him, but it is a business first, and if Antonio is not here, we are going to have to hold the fort down until he gets back.”

That’ll be a big task, considering Gates accounted for nearly 20 percent of the offense last year.