New England Patriots coach

Bill Belichick

lashed out at the team's former video assistant yesterday, saying in a televised interview that

Matt Walsh

was a low-level staffer who was fired for "poor job performance."

"There's not a lot of credibility," Belichick said in an interview broadcast on

CBS Evening News

.

"You know, he's tried to make it seem like we're buddies and belong to the same book club and all. That's really a long, long stretch."

Belichick acknowledged that he violated NFL rules prohibiting filming opponents' signals but insisted there was no intent to hide what he was doing.

"I made a mistake," he said in the interview. "I was wrong. I was wrong."

NFL commissioner

Roger Goodell

previously fined Belichick $500,000 and docked the Patriots $250,000 and a first-round draft pick.

NFL owners could opt out of their agreement with the players' union next week, leaving open the possibility of a 2010 season without a salary cap.

The labor agreement is on the agenda for the league meetings in Atlanta on Tuesday.

Gene Upshaw

, the executive director of the NFL Players Association, said yesterday that if it doesn't happen Tuesday, it will happen soon.

In the agreement signed in March 2006, both sides were given the right to get out of the deal by Nov. 8, 2008.

League officials noted that doesn't mean that a decision couldn't be made earlier.

Tennis

Serena Williams

withdrew from her quarterfinal match at the Italian Open yesterday because of a back problem, and older sister

Venus Williams

was beaten by defending champion

Jelena Jankovic

, 5-7, 6-2, 6-3, with the American committing 57 unforced errors to the Serb's 24 in Rome.

Defending champion

Roger Federer

cruised into the semifinals of the Hamburg Masters by defeating

Fernando Verdasco

, 6-3, 6-3, in Germany.

Novak Djokovic

also made the final four, downing

Albert Montanes

, 6-2, 6-3. Djokovic will face

Rafael Nadal

, who defeated

Carlos Moya

, 6-1, 6-3.

Track and field

Olympic gold medalist

Tim Montgomery

's once-celebrated life continued its long downward spiral when a federal judge in White Plains, N.Y., sentenced the former "world's fastest man" to nearly four years in prison for dealing in bad checks.

The judge also warned Montgomery, 33, that the evidence against him "does not appear to be flimsy" in an ongoing case in Virginia, where he is accused of selling heroin. A conviction there would carry a minimum mandatory five-year sentence.

Auto racing

Veteran driver

Ryan Briscoe

, a front-row qualifier last week, crashed hard in the second turn but was uninjured during practice for the Indianapolis 500.

In separate crashes, rookie drivers

E.J. Viso

and

Will Power

also hit the wall but were not hurt.

Final qualifications are tomorrow.

Elliott Sadler

took the pole ahead of

Brian Vickers

for tonight's Sprint Showdown at Lowe's Motor Speedway in Concord, N.C., while

Kyle Busch

took the pole for the Sprint All-Star race at the same site.

Colleges

Running back

George Stripling

was dismissed from the Louisville football team for a violation of team rules.

He ran for 1,338 yards and 13 touchdowns in 34 career games.

Temple beat host St. Louis, 7-6, in the opener of a doubleheader that enabled the Owls baseball team to qualify for Wednesday's Atlantic Ten tournament at Campbell's Field in Camden for the first time since 2002.

Former St. John's and George Washington basketball coach

Mike Jarvis

is a candidate to take over Florida Atlantic's program but has not been offered a contract, a school spokeswoman said in Boca Raton.

Hockey

Rick Nash

scored the go-ahead goal to put host Canada in the title game of the world hockey championships with a 5-4 win over Sweden in Quebec City.

Tomorrow, Canada will face Russia, which advanced with a 4-0 shutout of Finland. It's the first time the two hockey powers have met for the world title. The Swedes will play rival Finland today for the bronze medal.

Swimming

Natalie Coughlin

broke her own American record in the women's 100-meter freestyle while finishing second at the Santa Clara Grand Prix in California in 53.39 seconds, bettering her previous record of 53.40 set March 2, 2007.

Australia's

Cate Campbell

, 15, won in 53.30 to set a U.S. Open record.