KANSAS CITY, Mo. — The cost of a franchise quarterback in the NFL is usually astronomical. The Kansas City Chiefs might have obtained one in return for a second-round draft pick — and picked up a starting linebacker in the deal as well.

The Chiefs won't know for some time whether 26-year-old Matt Cassel is the young star quarterback they've long sought. But if he is, they will look back on the trade they made Saturday with the New England Patriots as a steal — swapping the 34th overall pick in this April's NFL draft for Cassel and veteran Mike Vrabel.

The trade certainly carries some risk for the Chiefs. Cassel, a backup in college at Southern California, is a one-year wonder. He spent three years backing up superstar Tom Brady with the Patriots before being shoved into the lineup when Brady suffered a season-ending knee injury in last year's season-opener against the Chiefs.

Cassel went on to have a solid season, throwing for 21 touchdowns and 3,693 yards and completing better than 63 percent of his passes. Vrabel will be 34 in August, so he doesn't figure to play many more seasons.

But if Cassel and Vrabel work out as the Chiefs hope, they paid an inexpensive price for a quarterback and a linebacker. Both are positions where the Chiefs had little stability in recent seasons.

Cassel can step in as the Chiefs starter because Kansas City's remaining quarterbacks — Tyler Thigpen, Brodie Croyle, Quinn Gray and Ingle Martin — are a combined 1-18 the last two seasons. Croyle, once hoped to be the QB of the future after being drafted in 2006 out of Alabama, has yet to win a NFL game and is coming off a season-ending knee injury. Damon Huard, who with Thigpen led the Chiefs to their only two victories last season, was released last week.

The Chiefs are also paying Cassel plenty, but money is no object for them. Cassel recently signed a one-year contract with the Patriots paying him $14.65 million — which will be the highest on the Chiefs — but Kansas City had about $50 million of room under the NFL-imposed salary limit of $127 million before the trade.

The Patriots were looking to clear some cap room of their own. Cassel was expendable because New England believes Brady's knee will be sufficiently healed by the start of the season.

The trade frees the Chiefs to pass on the top available quarterbacks in the draft, Matt Stafford of Georgia and Mark Sanchez of Southern Cal, and use their first-round pick, third overall, on a different position.

Chiefs general manager Scott Pioli and coach Todd Haley declined to answer questions about the trade. Pioli acknowledged in a statement released by the Chiefs that he felt comfortable making the move because of his familiarity with Cassel and Vrabel.

Pioli was New England's personnel director for nine seasons before he joined the Chiefs in January. He was with the Patriots in 2001 when they signed Vrabel as a free agent from the Steelers and in 2005 when they drafted Cassel.

Cassel would have remained buried on the bench behind Brady and an unknown quantity if not for the Chiefs and safety Bernard Pollard, who crashed into Brady's knee during last year's game against the Patriots.

Cassel finished up that day, completing 13 of 18 passes for 152 yards and a touchdown. The Patriots beat the Chiefs, 17-10.

"He came in and did well against us, maybe played better than we thought he'd play," Chiefs safety Jarrad Page said. "That was really the first time he was in the game when it was still up for grabs.

"I remember when I was at UCLA, he played tight end a little bit for USC. So you know he's a tough guy. He'll take the ball and run. He's definitely not Michael Vick, but he'll tuck the ball and run when he gets the chance. That's one thing they prepared us for before we played them. We also knew he could throw the ball. Why else would the Patriots draft him when he didn't play in college? They obviously felt he could come in and be a good quarterback."

Cassel started the other 15 games and the Patriots won 10 of them, finishing 11-5 but missing the playoffs.

"It is very easy to root for guys like Matt Cassel who do everything the right way and flourish as a result," New England coach Bill Belichick said in a statement released by the Patriots. "As much as we would have loved to continue working with Matt, we wish him nothing but the best as he takes this next step forward in his career."

While Cassel is the headliner in the deal, the Chiefs probably aren't looking at Vrabel as a throw-in. While he won't have a long-term impact in Kansas City, he can help the Chiefs transition to a 3-4 defense and gives the Chiefs another veteran linebacker to join Derrick Johnson and Demorrio Williams.

Vrabel, an eight-year starter for the Patriots and a member of all three of New England's Super Bowl championship teams, can also provide some leadership for a defense that has lacked in that area.

"When Mike arrived in 2001, we knew we were adding a solid outside linebacker," Belichick said. "But where Mike took it from there exceeded our highest hopes. Mike Vrabel epitomizes everything a coach could seek in a professional football player: toughness, intelligence, playmaking, leadership, versatility and consistency at the highest level.

"Of all the players I have coached in my career, there is nobody I enjoyed working with more than Mike. He is one of the very special Patriots champions."