I promise I'm going to stop doubting Ben Roethlisberger. The veteran signal-caller has reached into the fountain of youth recently en route to an impressive showing in fantasy football. 

He threw 66 times against Baltimore in week 14, going for more than 500 yards and two touchdowns. Game flow dictated that number and that's not a volume you should expect going forward.

However, he's been chucking it more often lately, so he should earn a start once again in week 15 against New England. For the rest of the best bets during semifinal week, here's the week 15 quarterbacks start 'em, sit 'em guide in fantasy football. 


Jimmy Garoppolo vs. Tennessee Titans

For you fantasy football owners still alive and streaming your quarterbacks, here's your answer for week 15. 

He's efficient. The 49ers are moving the ball up and down the field. And he has a decent matchup. 

Garoppolo finished with more than 300 yards passing in week 14 and one touchdown against a below-average Houston team. Besides all the stats, this offense looks much better, and actually should increase Carlos Hyde's fantasy outlook going forward, too. 

The Titans rank in the bottom-half of the NFL in fantasy points allowed to quarterbacks, and are in the bottom-10 in the NFL in passing yards allowed. 

This game will equal back-to-back road tilts for the Titans against a San Francisco team quietly on a two-game winning streak. I love the matchup and anticipate Garoppolo to deliver for fantasy football owners. 

Derek Carr vs. Dallas Cowboys

Carr has been inconsistent. And the Raiders are a major disappointment. 

But this spot isn't bad for Carr, depending on your quarterback situation. He's going to be volume-heavy with his passing attempts, and the Cowboys aren't good at stopping opposing quarterbacks. 

In the last three games, Dallas has allowed the second-most passing yards per game at 295. Dallas also ranks 11th-worst in fantasy points allowed to quarterbacks. 

Carr has the opportunity to be a top-12 fantasy quarterback this week. If you have some question marks at that position, believe in Carr as a QB1. 

Case Keenum vs. Cincinnati Bengals

At one point this season, this matchup would be highly avoidable. Thanks to injuries and a renewed chance with the Vikings, Keenum shouldn't be passed up based on earlier results this season. 

The Bengals used to rank in the top-five in fantasy points allowed to quarterbacks. That's not the case anymore, with the Bengals now allowing 15.4 fantasy points per game to quarterbacks, the 12th-best mark in the NFL. 

It's not all the Bengals fault. Injuries have decimated that defense. In the last three games, though, the eighth-ranked passing defense overall is giving up 256 passing yards game, the 10th-highest amount in that time frame. 

And Keenum isn't Mitchell Trubisky, which the Bengals couldn't stop either last week. Keenum is going to throw for touchdowns (at least two touchdowns in five of the last six games) and he has plenty of volume. 

Don't believe in the Bengals defense. Things change, so Keenum is safe to start in week 15. 


Alex Smith vs. Los Angeles Chargers

I had a weak moment in week 14 and started Smith. The matchup was good, but Smith disappointed. 

This week offers a much more difficult mountain to climb, so I'll back off Smith. After his torrid start to the season, Smith has been...well...Alex Smith. He's been pedestrian in every week but one since week 8. 

The volume isn't horrible, but he's just not throwing for enough yards to justify his inability to score touchdowns. Outside of his four-touchdown day in week 13, he has a combined four touchdowns since week 8.

That's not enough to get it done against a Chargers defense consistently good against the pass. Los Angeles is allowing 168 yards passing per game in the last three games, so the Chiefs will have to run it often to try to break through.

The volume won't even be there this week for Smith, so find a different option for week 15.

Marcus Mariota vs. San Francisco 49ers

If you have Mariota in your lineup, you're probably not in the fantasy football semifinals anyway, but just in case you are, I would find a different option this week. 

Mariota has been one of the most disappointing fantasy plays in 2017. In a blizzard, Nathan Peterman outscored Mariota in week 14; that's just how far Mariota has fallen. 

Tennessee's offense is like watching paint dry and Mariota isn't helping it. Since week 9, Mariota has 10 interceptions compared to eight touchdowns.

And while this matchup is generally a nice one to exploit, I wouldn't take the bait. Mariota is even worse on the road, going for three touchdowns and eight interceptions in his last three road games.

Ignore the tasty matchup and keep Mariota on the bench.

Jameis Winston vs. Atlanta Falcons

I don't trust Tampa Bay. That's why in my semifinal match, Winston is grabbing a seat on my fantasy bench. 

When I targeted Winston before the season, I anticipated growth in the turnover department. Other than his injury, Winston has been doomed by his knack for turning over the football. 

What would have been a nice fantasy day in week 14 turned into an average one, thanks to two interceptions and a fumble. And he was mostly ineffective throughout the day, other than a strong fourth quarter, which was aided by game flow. 

Atlanta has been good this season against the pass, allowing 211 yards per game, the sixth-best mark in the NFL.

The Buccaneers should try to run the football against the Falcons, so that will diminish Winston's throwing opportunities. He's on the borderline for QB1/2, but there are other options better than Winston in week 15. 

Scott Levine is the Associate Editor for the Clinton Herald. During his free time, he blogs about fantasy sports and handicaps games. Check out more at Against The Chalk.

Scott Levine can be reached at scottlevine@clintonherald.com or on Twitter @ScottLevineCH