Alex Smith has signed a four-year contract extension with the Kansas City Chiefs worth $17 million per season.

Smith's deal includes $45 million in guaranteed money.

The Chiefs dealt for Smith from the San Francisco 49ers for two second round picks.

“It was a priority of ours to get this deal done and keep Alex in a Chiefs uniform long-term,” general manager John Dorsey said in a statement. “Alex is a proven leader on and off the field. He is a special individual with a lot of ability, and we are fortunate to have him here.”

Bill Belichick is ranked as the best coach in the NFL, according to a poll of 30 league insiders.

Pete Carroll and Sean Payton are ranked second and third and are also in their first tier.

"The most important thing to me is the ability to control the offense, the defense and the special teams," a GM said in describing the ideal coach. "You can change and you can coach multiple things and you have the ability to teach almost every position group. Then you can lose any coach you want and replace from within because the head coach is the talent. Belichick is the ultimate model of that."

Belichick commmanded a 1 vote on 28 of 30 ballots.

In Tier 2 are Andy Reid at No. 4, Tom Coughlin at No. 5, Mike McCarthy and Mike Tomlin at No. 6, Jim Harbaugh at No. 8, John Harbaugh at No. 9, John Fox at No. 10 , Jeff Fisher at No. 11, Chip Kelly at No. 12, Bruce Arians at No. 13, Lovie Smith at No. 14 and Mavin Lewis at No. 15.

Tier 3 is led by Chuck Pagano At No. 16, followed by Rex Ryan (17), Mike Smith (18), Gus Bradley (19), Ken Whisenhunt (20), Mike McCoy (20), Marc Trestman (22) and Ron Rivera (23).

Tier 4 features Mike Zimmer (24), Jay Gruden (25), Bill O'Brien (26), Jim Caldwell (27), Doug Marrone (28), Joe Philbin (29), Jason Garrett (30), Mike Pettine (31) and Bruce Allen (32).

Donald Stephenson has been suspended for four games by the NFL for a violating policy on performance enhancing substances.

The Kansas City Chiefs already had depth issues on their offensive line.

"Obviously losing Donald is disappointing, but we are in full compliance with the league's policy," the team wrote on the its official website. "We will have no further comment on the situation."

Dwayne Bowe will be suspended for one game for violating the NFL's substance abuse policy.

Bowe was arrested for possession of marijuana last fall and was suspended four games for violating the PED policy in 2009.

Bowe is the Kansas City Chiefs' No. 1 receiver.