St. Louis Rams (2-4) at Kansas City Chiefs (3-3)

Sunday, 1:00 p.m. ET, at Arrowhead Stadium, Kansas City, Mo. — TV: FOX

*TV announcers: Dick Stockton, Donovan McNabb, Kristina Pink

*Keys to the game: The Rams are increasingly relying on their impressive rookie class, including RB Tre Mason, who logged 18 carries for 85 yards against Seattle last week. Second-year QB Austin Davis, who had struggled with bouts of poor decision making under pressure, thrived with a more conservative game plan as he completed 17 of 20 passes and a pair of touchdowns. Twelve of those completions went to backs and tight ends. The Rams will be content to play a field position game and rely on their high risk/high reward special teams to come up with a game-changing play or two.

Chiefs QB Alex Smith has an enormous experience edge on his counterpart and has been playing excellent football over the past month. He, too, will take what the defense gives him as Kansas City has no desire to let the Rams’ resurgent defensive line dictate the game. Smith has to be careful against St. Louis’ aggressive young secondary that tends to gamble — leading to big plays one direction or the other. RBs Jamaal Charles and Knile Davis combined for 35 touches last week and are the best counter-weapons to a d-line that likes to get upfield, often leaving the league’s 28th-ranked run defense exposed.

*Matchup to watch — Rams DT Aaron Donald vs. Chiefs RG Zach Fulton: Donald worked his way into the starting lineup two games ago and wreaked all kinds of havoc against Seattle last week, including five tackles and a sack. Fulton is a sixth-round rookie who has started all six games, but is still learning on the fly. He’ll have a difficult time contending with the quickness of the 6-1, 285-pound Donald, but the Chiefs will be hard-pressed to protect Fulton much while also coping with Robert Quinn, Michael Brockers and William Hayes up front.

*Player spotlight — Rams LG Greg Robinson: Robinson also moved into the starting lineup two weeks ago. At 6-5, 332, his future is at left tackle while the Rams give the 22-year-old a softer landing spot inside. Raw but supremely athletic for his size, Robinson has upgraded the interior run-blocking.

*Fast facts: Rams leading rusher Zac Stacy (240 rushing yards) logged only one offensive snap last week and had no carries. … Smith has a 110.4 passer rating with eight TDs and 1 INT over his past three games.

WHO WILL WIN AND WHY

The Rams unloaded the special teams bag of tricks at home last week and still barely held off rival Seattle. On the road against a solid playoff contender, St. Louis’ youth is too much to overcome in the din of Arrowhead.

*Our pick: Chiefs 28-20