Cardinals vs. 49ers NFL Week 18 odds: Niners new NFC favorites, could steal top seed in Kliff Kingsbury's likely final game as Arizona coach

When the San Francisco 49ers lost quarterback Jimmy Garoppolo to a season-ending foot injury in Week 13, some in the NFL world wondered whether the Niners would even make the playoffs. The next quarterback up on the roster was rookie and Mr. Irrelevant Brock Purdy, after all. Yet here the Niner are, entering Week 18 against Arizona on a league-high nine-game winning streak and poised to take a shot at the NFC's top seed. It's widely expected to be Kliff Kingsbury's final game as head coach of the Cardinals with his team a 14-point underdog at Caesars Sportsbook.

If things go chalk in Week 18, the NFC West champion 49ers would be the conference's No. 2 seed and host Seattle, Detroit or Green Bay on wild-card weekend depending on what shakes out for the final spot among that trio (it will likely be the Packers).

An expected Niners win over Arizona and a Philadelphia loss at home against the Giants – rather unlikely as Eagles QB Jalen Hurts is expected back and New York has nothing to play for – would push San Francisco to the top spot in the conference and the lone first-round bye. Should San Francisco somehow lose this game and Minnesota win in Chicago, the 49ers would be the No. 3 seed and face the Giants on wild-card weekend.

Purdy got his chance under center too late to win NFL Offensive Rookie of the Year, but he'll get some votes. The last pick in the 2022 draft has become the fifth rookie QB ever to win each of his first four career starts, joining Ben Roethlisberger (won first 13 starts in 2004), Mike Kruczek (first six in 1968), Virgil Carter (first four in 1968) and Phil Simms (first four in 1979). Purdy is also the seventh rookie QB in the Super Bowl era with at least two touchdown passes in five consecutive games and the first since the Chargers' Justin Herbert in 2020.

The nine-game winning streak is the Niners' longest this century. That run, coupled with the Eagles' back-to-back losses, has San Francisco positioned as the new favorite at Caesars to win the NFC (+180) over Philadelphia (+200).

Meanwhile, Arizona might be a bigger mess than any other NFC team at 4-12 and on a six-game losing streak. Star QB Kyler Murry was lost to a torn ACL in November and might not be ready for the start of 2023. GM Steve Keim took a leave of absence and is not expected to be brought back. Neither is Kingsbury, the -300 clear-cut favorite to be the next coach fired – potentially right after this game, or on Black Monday.

Sunday will also be the last game for Cardinals defensive end JJ Watt. The three-time NFL Defensive Player of the Year and future Hall-of-Famer will retire at age 33. Watt has had trouble staying healthy in his stellar career but has done so this year and has 10.5 sacks in 15 games. 

• Picks: NFL | NBA | CFB | CBB
• DFS: Lineup Optimizer | Picks
• Early Edge: YouTube | Apple Podcasts
• Newsletters: SportsLine Daily | Fantasy

Qualifying SportsLine members receive a 30-day free trial of Paramount+ premium. Sync your account right here.