It feels like it's at least three times every season a different Patriots running back puts together an outstanding performance and raises a lot of eyebrows in the fantasy football universe. The most recent culprit is Jonas Gray. Hot off of 38 carries for 199 yards and 4 touchdowns against the Colts, Gray is tempting a lot of owners to hit the "add player" button. One of his biggest drawbacks is simply the fact that he's in the notoriously difficult to predict New England backfield. In an attempt to bring at least a little bit of clarity to the situation, let's look at whether we can trust Gray in our fantasy backfields.

Success and Upside

As we saw on Sunday night, Gray definitely has the potential for massive, game-winning fantasy performances. While this big game came against a Colts defense that was ranked 23rd against the run going into the game according to our Adjusted Net Expected Points (NEP) metric, it was easily a big enough showing that it's still incredibly impressive despite that context.

Among backs with 50 or more carries this season, Gray is at the top of the pack in terms of both Rushing NEP per carry and success rate (the percentage of carries on which a back posts a positive NEP). Also sitting in the top-10 for success rate is Stevan Ridley, a promising sign if you had any concern about the Patriots offensive line.

Being in the Patriots Backfield

One thing that holds true in fantasy football year-in and year-out is that a player can have all the potential and upside in the world, but without opportunity, that potential simply wont translate into consistent fantasy points.

The tricky thing about the New England backfield is that the opportunity for Gray will likely be there again - just not every week. To be able to get the most value out of him you have to try to identify which games he'll see heavy usage, and which games he'll only see five touches. (No Patriots back in the last two seasons has recorded a 15-plus carry game without also recording at least one game with 5 or fewer carries in the same season).

In October, we took a look at Shane Vereen's big games, and whether we could predict them. A lot of what JJ Zachariason looks at in that article can be turned around to try to identify which games will see success for backs that aren't Vereen. (He predicted the Colts game as a run-heavy one, and that worked out fairly well).

If we take a look at the big games for the Patriots' workhorse backs (Ridley pre-injury, and Gray recently), it become immediately clear how matchup-dependent they are.

"Carries" refers to carries recorded by the Patriots lead back for the day, Ridley in the first three and Gray in the final two. The defensive rankings are where they sat leading up to the game.

Opponent Carries Run D Rank Pass D Rank Vikings 25 12 1 Raiders 19 21 25 Bengals 27 30 1 Bears 17 27 16 Colts 38 23 11

With the sole exception of the Raiders game, each 15-plus carry performance for Patriots running backs this season has come against a team whose run defense was much weaker than its pass defense. This holds especially true for the three 20-plus carry games. New England has yet to play a bottom-half run defense this year without recording at least 15 carries for their top back.

Remaining Schedule

So what does this mean for Jonas Gray? Let's take a look at the Pats' upcoming schedule:

Opponent Run D Rank Pass D Rank Lions 1 7 Packers 23 12 Chargers 14 29 Dolphins 16 1 Jets 14 22

There are two good-looking matchups in there, the Packers in Week 13 and the Dolphins in Week 15. The Jets matchup in Week 16 also offers some promise simply because the Patriots should be playing with a sizable lead - our nERD metrics currently favor the Patriots by more than 12 points against the Jets - but is not one I'd feel particularly comfortable playing Gray.

Gray's Outlook

To me, Jonas Gray is only startable for those two favorable matchups. A back like Gray, who offers nothing in the passing game, is so volume dependent that the risk of him only seeing five or six touches in a game will keep him out of all of my lineups on any other week.

The nice thing is that as bye weeks start to wind down, you should have some more room to maneuver with your bench spots, and if you're weak at running back Gray could be a difference-maker for you in Weeks 13 and 15.

So while I won't be trusting Gray as a rest-of-season option, I'd be very comfortable plugging him into a lineup hurting for running backs for those games. We just have to hope Belichick doesn't decide it's time for Brandon Bolden's breakout game.