Bob Sanders' big hits have finally paid off in a big way.

The two-time Pro Bowler agreed to a five-year contract extension yesterday, a deal that will keep him with the Indianapolis Colts through 2012 and makes him one of the league's highest-paid safeties.

The deal is worth $37.5 million and includes $20 million in guarantees, a person familiar with the negotiations told the Associated Press on condition of anonymity because the deal had not yet been announced.

Sanders' average salary of $7.5 million under the extension is nearly $1 million more than what Pittsburgh's Troy Polamalu got in his new deal in July, and the guaranteed money is more than what Ed Reed got when he signed an extension with the Ravens in June 2006.

Colts receiver Marvin Harrison will likely start tomorrow night against the Tennessee Titans after practicing a second day in a return from a left knee injury that has sidelined him most of the season.

Drug testing.

Nearly all of the NFL's former drug-testing agents filed a federal lawsuit in New York, saying they were fired and effectively blacklisted because of a labor dispute.

The drug testers - most of whom were retired FBI and DEA agents - were replaced en masse this year after the league decided to outsource the job of collecting player urine samples to an independent company, Comprehensive Drug Testing of Long Beach, Calif.

That drug-program overhaul took place amid a campaign by the NFL's then-sizable force of testing agents to have themselves declared league employees, rather than independent contractors.

In a lawsuit filed in U.S. District Court in Manhattan , 93 former drug-program agents said the NFL's firings were retaliation for the attempt to clarify their employment status.

Falcons coach.

Mike Singletary, a Hall of Fame linebacker when he played for the Chicago Bears, would not elaborate on his interest in pursuing the Atlanta head coaching position for a second straight year.

A year ago, Singletary - the San Francisco 49ers' assistant head coach - was a finalist in the Falcons' coach search. The Falcons instead hired Louisville coach Bobby Petrino, who this year quit after only 13 games to take the job at Arkansas.

Singletary said this week he would "absolutely" have interest in the Atlanta job, but yesterday he relayed word through 49ers spokesman Aaron Salkin that he "did not want to address Atlanta at this time."

Emmitt Thomas has been the interim head coach for the final three games. The Falcons (3-12), who have lost six straight, end their season tomorrow with a home game against Seattle.

Fines.

The NFL fined Texans defensive tackle Travis Johnson $5,000 for a late hit on Colts tight end Bryan Fletcher during Sunday's loss to Indianapolis.

The unnecessary-roughness penalty was the second of the game for Johnson, who was earlier flagged for a late hit on Peyton Manning after the quarterback was sacked by Mario Williams. The NFL confirmed the fine.

The NFL also fined official Jim Quirk one game check for inappropriate physical contact with players, including Green Bay Packers linebacker Nick Barnett.

The fine totals $8,150, NFL spokesman Greg Aiello said.

The decision came after Quirk grabbed Barnett by the neck and threw him to the ground while breaking up a scuffle during the Packers' loss at Chicago on Sunday.

Elsewhere.

Buffalo starting safety Donte Whitner is questionable for the Bills' season finale at the Eagles tomorrow after missing his third straight practice with the flu. . . . Denver wide receiver Rod Smith, 37, revealed that his surgically repaired left hip hurts more than ever and that a specialist in Los Angeles will resurface or replace the joint in January. . . . Wide receiver Terrell Owens and cornerback Terence Newman were among four Dallas starters declared inactive for the Cowboys' regular-season finale at Washington. . . . Chris Weinke will be the fourth starting quarterback this season for San Francisco when he replaces the injured Shaun Hill at Cleveland tomorrow. . . . Reggie Bush is out for New Orleans' game tomorrow at Chicago.