Five things you need to know about the Chiefs:

1. Ready to air it out: The Chiefs' passing game excelled under former offensive coordinator Charlie Weis last season, and don't expect that to change now that Weis is at Florida. Offensive line coach Bill Muir has been promoted to offensive coordinator. Former Washington head coach Jim Zorn is the quarterback coach, and head coach Todd Haley will be involved in the passing game. Don't expect the Chiefs to shy away from throwing the ball. If you don't believe it, just look at two of their biggest offseason pickups -- receiver Jon Baldwin, their first-round pick, and free-agent slot receiver Steve Breaston.

2. It all starts with Jamaal Charles: The Chiefs are in fine shape at running back. They just signed fullback Le'Ron McClain, who runs the ball more than the typical fullback, and they still have veteran Thomas Jones. Those two will help keep pressure off star Jamaal Charles, who the team believes is most effective when he is fresh. Jones had 15 more carries than Charles last year. That will probably change because Charles is so explosive. According to the Football Scientist, KC Joyner, Charles is outstanding in his good blocking yards per attempt (GBYPA) metric. It gauges how productive a running back is when his blocking is effective. Charles had a 9.0 GBYPA last year, second best in the NFL.

3. Challenge will be stiffer in 2010: The Chiefs were a surprise division winner last year. They developed quickly and showed they are one of the NFL's most talented young teams. However, they benefited from an easy schedule. Kansas City played only two playoff teams in 2010. The schedule toughens this season. From Weeks 11 to 15, Kansas City plays five 2010 playoff teams, including the four teams that went to the conference championship games: Green Bay, Chicago, Pittsburgh and the New York Jets. The other 2010 playoff team in that mix is New England. Yes, it's brutal.

4. Varied weapons: Kansas City has a unique offense. No weapons are alike. The Chiefs will feature receivers Dwayne Bowe, Baldwin and Breaston. They all offer different things. Bowe is a classic No. 1 type. Baldwin is a big, vertical threat. Breaston is a chain-mover. Add field-stretching tight end Tony Moeaki and shifty running back/receiver Dexter McCluster, and the Chiefs will have many different schemes to keep defenses off balance.

5. Hali was not a one-hit wonder: Don't expect Tamba Hali to fade now that he got his big contract. The Chiefs recently gave Hali a five-year, $60 million deal with $35 million guaranteed. He is not a cash-grab type of player. He is very humble and is a hard worker. Expect Hali, who led the AFC with 14.5 sacks last season, to work even harder to live up to his big contract.

-- Bill Williamson, ESPN.com

Matt Cassel had an impressive 2010 season, leading the Chiefs to a division title while throwing 27 TDs and only seven interceptions. Cassel's passer rating of 93.0 ranked eighth in the NFL.

In total QBR, however, Cassel ranked 16th among 33 qualified passers in 2010 with a 51.2 (average is 50.0). He ranked just behind Kerry Collins and just ahead of Ryan Fitzpatrick. Although Cassel's basic stats were impressive, the Chiefs' quarterback saw his performance dip in critical late-game situations, which are weighted more heavily in total QBR. He completed nine of 25 passes (36 percent) and was sacked three times in the fourth quarter when Kansas City was tied or trailing by a touchdown or less.

Cassel also did not do much to help the offense spread the field. He averaged just 8.0 air yards per pass attempt, which ranked 22nd among qualifying quarterbacks.

He made few mistakes, but they came at bad times. Of Cassel's seven interceptions, five came with the Chiefs tied or trailing by a touchdown or less.

• Dwayne Bowe led the league with 15 touchdown receptions, including eight of the team's nine touchdowns on throws 15 or more yards downfield last season. Bowe had 25 total receptions on throws of 15 or more yards; the rest of the team combined for 10.

• Tamba Hali finished second in the league in sacks with 14.5, including 9.5 when the Chiefs featured at least five defensive backs. Twenty-four of the Chiefs' 39 sacks came when they were playing at least five defensive backs.

-- ESPN Stats & Information