Fantasy Sports

Sam Darnold or Baker Mayfield? Week 18 Fantasy Football Start/Sit Guide

Debating a start/sit between these two quarterbacks? We dive deeper than the projections to help make the right decision. 
Michael Rovetto|
Dec 28, 2025; Charlotte, North Carolina, USA; Seattle Seahawks quarterback Sam Darnold (14) throws a pass against the Carolina Panthers during the fourth quarter at Bank of America Stadium. Mandatory Credit: Jim Dedmon-Imagn Images
Dec 28, 2025; Charlotte, North Carolina, USA; Seattle Seahawks quarterback Sam Darnold (14) throws a pass against the Carolina Panthers during the fourth quarter at Bank of America Stadium. Mandatory Credit: Jim Dedmon-Imagn Images | Jim Dedmon-Imagn Images

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Tampa Bay BuccaneersSeattle Seahawks

Sam Darnold and Baker Mayfield are two quarterbacks with similar stat lines in fantasy football this season, despite many having contrasting preseason expectations for each. 

Darnold has exceeded expectations. He’s QB15 on the season while throwing for 3850 yards, 25 touchdowns and 14 interceptions. Mayfield, on the other hand, has fallen short of expectations. He’s QB13 on the season, with 26 total touchdowns and 10 interceptions. 

Many platforms have the two QBs ranked neck and neck heading into Week 18, when many are playing for a fantasy football title. However, one option is far better than the other. Still, let’s dive deeper into the numbers by making the case for each before making a final decision. 

The Case For Darnold 

Darnold is ranked between the QB 10-15 range on most platforms. He and the Seattle Seahawks face the San Francisco 49ers in Week 18. The game has an over/under total of 47.5, which is relatively modest. The 49ers' defense is one of the most injury-plagued units in the NFL. They’re allowing nearly 30 points per game over their last three. 

The 49ers also boast a high-powered offense, which has averaged 42 points per game over their last three games. This is a game that can turn into Week 16’s overtime thriller between the Seahawks and Rams. Seattle overcame a 16-point deficit and won 38-37, behind Darnold’s 270 passing yards and two touchdowns. 

Darnold’s fantasy value is largely matchup-based, and he has an advantageous matchup this week. San Francisco allows the 13th-most fantasy points to opposing signal callers per game. We have Darnold projected to finish as QB11 in Week 18, posting 21.05 fantasy points. 

The Case For Mayfield 

Mayfield has struggled from Week 7 onward, recording just two games with 19 or more fantasy points from that point. The good news is that he’s been slightly better lately. He posted 277 yards and two passing touchdowns for 19.18 fantasy points against the Atlanta Falcons in Week 15. He’s also coming off a 346-yard passing performance, where he threw two TDs against the Miami Dolphins.

Mayfield and the Tampa Bay Buccaneers play the Carolina Panthers in Week 18. The Buccaneers can clinch the NFC South with a win and a Falcons loss. This makes it challenging to bet against Mayfield, who virtually needs to deliver one of his better performances. The Buccaneers are losers of seven of their last eight. 

Chris Godwin also returned to his pre-injury form, going for 108 yards and a touchdown on seven receptions last week. Mayfield has some of the best weapons in the NFL. Although the Panthers’ defense has been good against the pass in 2025, the Buccaneers should be a tough matchup for them a second time around. 

Final Verdict

Fantasy managers should start Darnold over Mayfield in Week 18. Darnold has a lower floor, but his upside is much greater. The Seahawks will be forced to pass to keep up with the 49ers’ potent offense. This gives Darnold more opportunities. I expect him to throw multiple touchdowns in a game that looks like a shootout. 

Mayfield posted just 12.7 fantasy points the last time he faced the Panthers in Week 16. He threw for only 145 yards, one touchdown and an interception. He and his inconsistencies can’t be trusted a second time around against a Panthers’ defense that allows the sixth-fewest fantasy points per game to QBs. 

Darnold was featured on my list of QBs to start in Week 18, while Mayfield made my list of sits. Trust Darnold over Mayfield with your fantasy title on the line.

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Michael Rovetto
MICHAEL ROVETTO

Michael Rovetto previously served as the staff writer for University of Maryland Athletics for nearly two years. There, he wrote, edited and managed all editorial content for all 20 of Maryland's varsity sports on umterps.com. Rovetto is recognized as a College Sports Communicators district award-winning writer. Many of his stories have also appeared on NCAA.org, garnering national attention. Before graduating from Maryland's Philip Merrill College of Journalism in December 2023, Rovetto wrote for PressBox and Terrapin Sports Central, covering Maryland men's basketball and football. He also has experience in broadcasting, previously working as an analyst and camera operator for Big State Sports, and communication, interning for Shell Shock TBT as its Director of Communication & Content Development.

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