The Seahawks are the first sub-.500 division champs in league history, taking the title with a 16-6 win over the St. Louis Rams last night. Their reward: a home game Saturday with the defending Super Bowl champion Saints. New Orleans beat the Seahawks, 34-19, in Week 11.

Making his second career start, backup quarterback Charlie Whitehurst threw a 4-yard touchdown pass on Seattle’s first possession, and Olindo Mare kicked three second-half field goals.

The situation in the NFC West this season has reignited the debate whether division champs should automatically be granted home playoff games. The New York Giants and Tampa Bay have better records at 10-6, but it’s Seattle that’s playoff bound, a division winner for the first time since 2007.

“We didn’t get here the way we all dreamed of getting here, but we got here,’’ Seattle coach Pete Carroll said.

St. Louis (7-9) was kept out of the end zone for the second time this season and rookie Sam Bradford couldn’t complete the Rams’ turnaround from winning just one game a year ago. Bradford finished 19 of 36 for 155 yards, and threw a costly interception midway through the fourth quarter.

Now the question for Seattle is who will be the quarterback for its first home playoff game since a January 2008 win over Washington.

Starter Matt Hasselbeck was active for the game and went through warm-ups, but Carroll held to his word the Seahawks were preparing for Whitehurst to be their guy after Hasselbeck injured his hip last week.

Whitehurst wasn’t spectacular, but he avoided critical mistakes, finishing 22 of 36 for 192 yards. His his lone TD was a 4-yard toss to Mike Williams in the first quarter.

Mare connected from 31, 38, and 34 yards.