A loud crash. A crumpled front end. A brief stay in an ambulance.

It was a very bad start to Tom Brady's day.

A new contract. The highest average salary in the NFL. A deal that ties him to the New England Patriots through 2014.

It was a very good ending.

The shaggy-haired star quarterback was involved in a two-car crash near his home in Boston's Back Bay at about 6:30 a.m. Thursday and was unhurt. One of the NFL's marquee players stood beside the damaged black Audi he had been driving with a fire engine behind him.

Then his day began to improve.

Brady made it to Gillette Stadium for the walkthrough practice beginning about 10:45 a.m. and participated with his teammates, all in full uniform, in a practice beginning shortly after 1 p.m. Everything appeared normal as he stretched then lofted passes to both sides of the field.

And then he wrapped up some unfinished business.

Brady agreed to a four-year contract extension beginning in 2011, two people with knowledge of the contract said Thursday night. It has an average annual value of $18 million — and a total of $48.5 million guaranteed, one of those persons said. Both spoke on condition of anonymity because the paperwork had not yet been filed with the NFL.

The extension was first reported by Peter King of Sports Illustrated during halftime of NBC's telecast of the Minnesota-New Orleans game.

This season Brady will make $6.5 million in the final year of a four-year extension that averaged $12 million.

The two-time Super Bowl MVP wanted to get his new deal done before the season opener Sunday at home against the Cincinnati Bengals, although he said he wouldn't let it distract him. Considering that he sustained a season-ending knee injury in the 2008 opener, having a deal in place before his first snap of the season provides security in case of another injury.

"I don't assume anything any more in life," Brady had said Wednesday when asked if he was excited about possibly being with the Patriots for a long time. "I don't think anything is guaranteed to us beyond what we have today and I really feel that way. That's the approach I've taken over the years, because you never really know when your last day will be."

Brady wants to play even beyond his new deal, which expires when he's 37. He's entering his 11th season and has said he'd like to play 10 more years.

"I think we're fortunate to get paid for something that we love," he said Wednesday. "There's no better job in the world that I'd rather have, to do what I'm doing. That's why I want to do it for a long time. Everything else in my life pales in comparison to how much I love this."

He kept doing it Thursday despite the car crash.

The 21-year-old driver of a red minivan involved in the crash, Ludgero Rodrigues, was cited Thursday for failing to stop at a red light, based on witnesses statements, police said. Two other people left the minivan and had no visible injuries, they said.

The police report didn't name Brady but said the driver of the Audi had no visible injuries and was evaluated by Emergency Medical Services. A 49-year-old passenger in the minivan was freed with the Jaws of Life and taken to a hospital.

Brady went to work.

From a sixth-round draft choice out of Michigan in 2000 to a three-time Super Bowl champion and 2007 NFL MVP, he has come from obscurity to reach the top of his sport. And now he's getting paid like it.

The average value of Brady's deal surpasses that of New York Giants quarterback Eli Manning, who agreed this year to a six-year, $97.5 million ($16.25 million average) extension starting next year. He's making $9.4 million this season.

Peyton Manning is in the final year of a seven-year, $98 million deal ($14 million average) and Indianapolis Colts owner Jim Irsay said he intends to make his quarterback the NFL's highest paid player.

But for now, after a very eventful day, that distinction belongs to Brady.