Week 15 Start Em, Sit Em: Breaking Down Top Boom-or-Bust Sleeper Judgment Calls

Now that the fantasy playoffs are in full swing, most owners are going to stand pat with their teams, barring a golden opportunity to cash in on a clutch sleeper to swing their matchups.

Deploying sleepers at this juncture of the NFL season, amid the thick of the playoff race, is a particularly risky strategy. Depending on how deep fantasy leagues are and the format, though, lesser-known commodities can be invaluable to a winning cause.

From personal experience, as an owner who went from second place to completely out of the playoffs this past week, fantasy is more luck than anyone likes to admit. Sleepers are even trickier to judge.

But let's take a look at two standout sleepers to start, along with a couple of others to sit in Week 15, who could make or break tons of fantasy postseason hopes.

Start: Johnny Manziel, QB, Cleveland Browns

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Cleveland Browns: Space Browns.

Yes, realms may collide, the Internet may crash, and FirstEnergy Stadium will feel like the Rock and Roll Hall of Fame for a day when Johnny Manziel makes his starting NFL debut in Week 15 against the Cincinnati Bengals.

With how poorly Brian Hoyer had played over the past month, some believed Manziel's time was meant to be Week 14 versus Indianapolis. Browns coach Mike Pettine described the logic that led to his sticking with his veteran, via NFL Network's Aditi Kinkhabwala:

That xenophobic mindset may have cost Cleveland a shot at the postseason. It remains to be seen. Hoyer lost to the Colts and had a horrible outing, and the Johnny Football era was finally permitted to begin.

Manziel is set up for success. He has an offensive coordinator in Kyle Shanahan who worked magic with Hoyer to start the year, helped Matt Schaub lead the NFL in passing with the Houston Texans and tailored an offense to suit Robert Griffin III's strengths during his electric 2012 rookie campaign.

The Browns need a spark at home and will be playing with their season on the line. For someone like Manziel, who's used to intense scrutiny and the big stage, he should thrive. This offense should rally around the dual-threat playmaker.

Cornerback Joe Haden also took issue with new Bengals starting running back Jeremy Hill's comments after the Browns' 24-3 win in Cincinnati in Week 10, when Hill said the Browns were "probably worse" than he thought, via ESPN Cleveland's Tony Grossi:

"

We've got [the comments] up. It's bulletin board material. You see what he felt about us. They're coming in here with something to prove. We went into their house on Thursday Night Football and did what we did to them. We know they're coming in here wanting to do the same to us, so we're ready for their best shot. We just feel, at the end of day, we're not getting the respect we want so we have to go out and keep doing it.

"

Haden also noticed that the rookie first-rounder is taking the chance to start seriously, via CBS Cleveland's Daryl Ruiter:

Here are some other factors to keep in mind. Cincinnati is dead last in the NFL with 15 team sacks, is without its top stud on the front seven in linebacker Vontaze Burfict, is 27th versus the run and has an aging secondary.

Oh, and there is little to no game tape on Manziel. Bengals head coach Marvin Lewis added kerosene to the fire when he referred to Manziel as a "midget" earlier this week.

Expect Johnny Football to reward fantasy owners with a couple long scrambling runs and to benefit from a full cast of weapons that features Pro Bowl pass-catchers in Josh Gordon and Jordan Cameron. As long as Cleveland can establish the run, get Manziel into play-action situations and let him use his legs, this should be a big-time performance from the Browns' long-awaited, hopeful savior at quarterback.

Projected Numbers: 190 yards passing, 2 TD, 1 INT; 60 yards rushing, TD

Sit: Teddy Bridgewater, QB, Minnesota Vikings

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For the University of Louisville in the prior two years, the Vikings signal-caller was the program's bridge over troubled waters. It's fair to say Bridgewater can't be anointed the face of the franchise in the Twin Cities just yet, but he's fared well under tough circumstances.

Without a proven feature back and behind a porous offensive line, play-caller Norv Turner has helped Bridgewater succeed at times, albeit with some rookie growing pains. Cleveland.com's Chris Fedor praised Bridgewater for his play:

Week 15 is not the time to roll the dice on Bridgewater in fantasy, though.

The Detroit Lions are scrapping for a playoff berth in the NFC and boast perhaps the best defense in the entire NFL west of Seattle. A havoc-wreaking front four is headlined by Ndamukong Suh, which should pose problems for the young Vikings passer.

Bridgewater has enough athleticism to make plays with his feet and has nice poise and feel in the pocket despite his diminutive frame. Seriously, he is the smallest-looking player in NFL history with supposed metrics of 6'2" and 210 pounds.

The positive traits Bridgewater is flashing with more frequency as he gains experience won't be enough to overcome Detroit's defense.

The Lions are joint seventh in the NFL with 35 sacks and the top-ranked team facing the run, so Minnesota will likely be rendered one-dimensional.

It seems irrational to lean on a first-year player in Manziel who hasn't made a single start as opposed to a more established newcomer like Bridgewater, but that's part of the game in fantasy football. Matchups carry a lot of weight, and this one isn't favorable for Bridgewater on Sunday at Ford Field.

Start: Martavis Bryant, WR, Pittsburgh Steelers

When a rookie fourth-round draft pick is already getting comparisons to the likes of Larry Fitzgerald and Randy Moss, it's safe to say that young receiver could be a special player.

In light of this stat from Sports Pickle's DJ Gallo, one could argue that Martavis Bryant is already exceeding expectations to a mind-boggling degree:

Bryant has flashed incredible skills—a rare blend of size and speed who could be even more lethal if he were more consistent.

Bob Labriola of Steelers.com has noticed where Bryant has fallen short at times:

But my goodness, when Bryant does put it together, it's marvelous. Take his 94-yard, game-changing touchdown catch in last week's win over the Bengals as a prime example. That marked Bryant's seventh TD snag in as many career games to date.

It turns out such a rate of paydirt production is pretty rare, per the NFL's Director of AFC Communications Jon Zimmer:

The Steelers get a crack at the Atlanta Falcons' last-ranked pass defense in Week 15 in the fast track of the Georgia Dome. Since Pittsburgh's secondary has had its own issues, it'd be a bit of a surprise if this game weren't an aerial showcase to behold with plenty of points on the board.

One of the most underrated players in the NFL is Falcons stud cornerback Desmond Trufant. He will draw Antonio Brown for the most part in coverage, leaving Bryant available to use his frame, elusiveness and improving grasp of the playbook to create a matchup nightmare.

Projected Numbers: 7 receptions, 120 yards, TD

Sit: Jonathan Stewart, RB, Carolina Panthers

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The car accident involving Panthers QB Cam Newton was a scary situation. His comments afterward were fitting, via NFL Network's Andrew Siciliano:

While Newton recovers and is thankfully in good spirits following the accident, it will be up to Derek Anderson to take over under center in Week 15.

Stewart's effectiveness benefits greatly from Newton's usual threat to run. Since Anderson will be strictly confined to the pocket, Carolina's offense won't be as diverse. That will lead to an underwhelming outing for those hoping Stewart builds on his past two games, where he's totaled 240 yards rushing and a TD.

Sunday's game in Charlotte will be a point of pride for the Buccaneers, who will be seeking revenge on Anderson, cram the box to stop Stewart and force the Panthers' typical backup QB to beat them through the air.

These thoughts from Panthers coach Ron Rivera on December 3 may entice fantasy owners to plug Stewart in as an RB2 or flex based on how he's done since, via Panthers.com's Max Henson:

Injuries have plagued Stewart throughout his career, however. Due to his hard-nosed running style, it's difficult to trust him after he's strung together two good games for the first time all season.

With the exception of a 57-yard run by Detroit's Joique Bell in Week 14, Tampa Bay has improved in defending the run in recent weeks. Gerald McCoy and Lavonte David on the front seven will help the Bucs as they gear up for a familiar foe and a more limited quarterback in Anderson.

Tampa can focus its efforts on stifling Stewart and will disappoint the fantasy owners who jumped aboard his bandwagon late in the year.