Week 15 and 16 are the most important weeks in fantasy football, as most league championships take place at some point during this vital two-week stretch. At this time of year, only the best owners are still alive, but their teams are likely bruised and battered and looking for a spark to get them to the promise land.

But as the great philosopher Ricky Bobby once said “If you ain’t first, you’re last.” So the objective when replacing injured studs like Adrian Peterson and Rob Gronkowski shouldn’t be to plug in low-upside slugs like Shonn Greene. Instead, owners should be mining for those untapped reservoirs of fantasy greatness.

These guys won’t be easy to find, so grab that shovel, and let’s go digging for some deep sleepers that might just win your league.

For quarterback sleepers, check out Waiver Wire Quarterback

Running Back

Chris Ogbonnaya (Owned in 14.4%) - Week 15: Chi | Week 16: @NYJ

With Willis McGahee looking doubtful for Week 15, Silent G would likely inherit a starters workload. Ogbonnaya has been extremely efficient this year on his limited carries, as his Rushing Net Expected Points per Rush of .15 ranks second in the entire league (min. of 35 carries).

He is also highly targeted in the passing game, which gives him a huge PPR boost. His 67 targets rank seventh among all running backs, and he could see from 6-8 targets if deemed the starter.

But the real reason Silent G should be plugged in your lineup is this week’s matchup. The Browns will play host to the Bears, the worst run defense in the league by every metric imaginable. When adjusting for schedule, Chicago ranks dead last in Defensive Rushing NEP, and sits 30th in fantasy points allowed to running backs, with an average of 22.7 points per game.

His luck may run out in Week 16 as the Jets own a top-five run defense, but Ogbonnaya should post RB2 numbers this week.

Toby Gerhart (Owned in 13.0%) - Week 15: Phi | Week 16: @Cin

With Adrian Peterson likely missing a couple of games with a foot injury, Gerhart will look to step in as the Vikings lead back (Gerhart is banged up himself, so keep an eye out for the injury report). The schedule isn’t easy, as Philadelphia and Cincinnati are both in the top half of the league when defending the run. But as long as Gerhart gets 15-plus carries, he will be usable.

Coming off of a 12.9-point effort against Baltimore, Gerhart is now averaging a whopping 7.9 yards per carry and sits atop the league in RNEP on his 36 totes (small sample alert). With volume being so essential for running backs this year, Gerhart looks to be a safe bet for at least 20 touches.

Jordan Todman (Owned in 1.2%) - Week 15: Buf | Week 16: Ten

Finding sleepers is all about capitalizing on opportunity, and injury replacements are the best way to do this. With Maurice Jones-Drew looking doubtful for Sunday, Jordan Todman looks to get his biggest workload to date.

Mojo has actually been quite solid himself, averaging steady RB2 numbers since Week 8, so a fresh set of talented legs like Todman's should be able to equal that sort of production with the same amount of touches. When accounting for volume, Todman and Mojo have the same RNEP per rush of -.07. With average matchups against the Bills and Titans, who rank 21st and 15th against the run, Todman could be a viable option.

Knile Davis (1.1%) - Week 15: @Oak | Week 16: Ind

Coming off a season-high 11 carries, Knile Davis looks to be the real deal backing up fantasy stud Jamaal Charles. However, Charles is still the unquestionable starter, making Davis purely a speculative add.

The Chiefs are all but a lock for the fifth seed in the AFC, and once locked up, could rest some of their guys in an attempt to keep them healthy before wild-card weekend. If Charles were to sit, Davis could run wild against three of the worst run defenses in the league, maybe winning some championships on the way.

Wide Receivers

Doug Baldwin (17.6%) - Week 15: @NYG | Week 16: Ari

It is becoming increasingly hard to depend on any facet of the Seahawks passing game, despite it being a top-five unit in terms of both scoring and NEP. Doug Baldwin might make you change your mind.

Baldwin has scored at least 7.6 standard fantasy points in four of his last five outings, and should continue that sort of production until Percy Harvin returns to the field. But as underrated as he has been for fantasy purposes, Baldwin is doing even better in real life.

Baldwin ranks third among qualifying wide receivers (min. 25 receptions) in Reception NEP per Target, which adjusts for his low but increasing volume. His schedule the next two weeks won’t do him any favors, as the Giants and Cardinals are above average against the pass, but I’d still check to see if Baldwin is lurking on your waiver.

Rod Streater (7.2%) - Week 15: KC | Week 16: @SD

Coming off a 7-130-1 line last week against the Jets, Streater simply isn’t getting the attention he deserves. With Denarius Moore out, Streater has taken over as the Raiders number one option when throwing by being targeted at least eight times in three of the past four weeks.

With the recent success of Matt McGloin, Streater’s Receiving NEP numbers have taken a huge leap, as he second year wideout’s Rec NEP/target of .84 sits right behind guys like Eric Decker and DeSean Jackson.

Kansas City is one of the better units in the league at defending the pass, although they can be beat deep, where Streater excels (second-most receptions of passes that travel 15-plus yards since Week 11). If he can weather the storm this week, he could pay huge dividends in Week 16 against the league’s sixth-worst pass defense in San Diego.

Cordarrelle Patterson (6.6%) - Week 15: Phi | Week 16: @Cin

After starting off the year averaging less than three targets per game, a criminal offense for a player this talented, rookie Cordarrelle Patterson is now averaging almost seven targets per game. In his 5-141-1 breakout last week, Patterson showed why he was in such high demand this spring during the draft process, taking a screen pass 79 yards to the house.

With that being said, CP is still quite raw, relaying on throws behind the line of scrimmage or deep down field. Because of this, he has a Reception Success Rate of 68.57%, the second-lowest mark in the NFL among wide receivers with at least 25 catches. This gives CP’s fantasy value quite the boom-or-bust feel.

But in the playoffs, sometimes all you need is a big play or two. When Patterson faces off against the Eagles 20th-ranked pass defense, one that allows the most fantasy points in the NFL to opposing wide receivers, I wouldn’t be surprised if Patterson makes an explosive play or two that produce some points.

Da’Rick Rogers (1.8%) - Week 15: Hou | Week 16: @KC

After bouncing on and off the Colts active roster all season long, highly-talented undrafted rookie Da’Rick Rogers finally made his NFL debut in Week 13, but failed to make a catch in 13 snaps. Last week against Cincinnati, Rogers busted onto the fantasy scene in a big way, recording six receptions for 107 yards and two touchdowns on 68% of the teams snaps.

To the dismay of many, the Colts offense still remains stagnant, but Rogers might be the spark-plug that Indianapolis and your fantasy team needed. With Andrew Luck seemingly taking a liking in Rogers, it’s looking like he could be the teams number two wide receiver the rest of the way.

He’ll have a chance to continue last week’s success in Week 15 against a Houston team that ranks 31st in the NFL when adjusting for schedule, and that have up over 35 points to Colts receivers in Week 9.