‪By Adam Harris‬-

(CBS) It’s no secret that the running back position has been very difficult for fantasy owners to fill this year, but more specifically, the RB2 slot this year is historically bad.

I define the RB2 fantasy running back as a back drafted in the middle rounds, originally slotted to complement the stud/breakout running back who an owner drafted in the first or second round. A good RB2 is reliable, steady and consistent. I generally aim for my RB2s to put up a minimum of 10 points a week, with the rare potential to break out.

The RB2 position is an X-factor in fantasy because it adds depth. Having a good one creates an advantage over the rest of the league that’s tough for opponents to overcome week in and week out. Last year there were plenty of RB2s to go around. San Diego’s Ryan Mathews, Green Bay’s Eddie Lacy, San Francisco’s Frank Gore, Denver’s Knowshon Moreno, Buffalo’s Fred Jackson and St. Louis’ Zac Stacy were all players drafted or picked up to fill a team’s RB2 slot, and they did so in amazing fashion.

This year is a different story. Before this past week, there were only a handful of guys who were playing a legitimate RB2 role. Jackson, Miami’s Lamar Miller and Indianapolis’ Ahmad Bradshaw were the most consistent and reliable RB2s in the game. After the Jackson injury this past weekend, that list is reduced to Miller and Bradshaw.

Miller followers have been waiting years for him to officially take over the No. 1 role in Miami, and he has finally done it. It took the signing of Moreno to get Miami to cut Miller’s nemesis, Daniel Thomas, and then it took Moreno’s elbow to explode to get Miller the carries. Thomas was re-signed (of course), but Miller has kept a firm grip on that lead role.

Miller has scored four times in the last three games, and he had a season-high 20 touches this past Sunday in Chicago. Miller is here to stay, and pending injury he’s one of the most valuable fantasy players in the game right now because he is so good in a completely depleted roe at RB2. Miller is a fantasy specialist, which makes his trade value and overall value skyrocket.

Bradshaw and Trent Richardson fight for touches and opportunity each week in Indianapolis, racking up similar yardage stats. Believe it or not, Richardson has outtouched Bradshaw by 26 total touches, but Bradshaw edges Richardson in touchdowns and receiving yards.

Bradshaw is clearly pass-happy Andrew Luck’s safety option in the red zone, with six scores through the air. This past week, Luck had a wide open Richardson inside the 5-yard line, and he didn’t even look at him. Richardson was jumping up and down and would have walked across the goal line, but Luck decided to take it himself. If that were Bradshaw, Luck would have stared him down.

Like Miller, Bradshaw is invaluable to a fantasy team that has him in the RB2 slot. There ‘s no depth at running back this year, with guys like Jacksonville’s Toby Gerhart, Tennessee’s Bishop Sankey, New England’s Shane Vereen, the New York Jets’ Chris Ivory, Cleveland’s Ben Tate, San Francisco’s Frank Gore and Tampa Bay’s Doug Martin underperforming. That list of backs was originally drafted to do just what Bradshaw and Miller are currently doing, but whether due to injury or poor play, all are failing miserably.

This leaves fantasy owners with the consistent five-point performance from the RB2 slot. That’s not a way to win consistently.

So be sure to value these fantasy RB2 heroes doing a thankless job each week. It’s time to give thanks to Lamar Miller and Ahmad Bradshaw for doing the blue-collar work that every fantasy back dreads. They score a consistent and reliable 10 points each week, paying complement to the stud RB1 on every owner’s team.

Adam Harris is a producer for 670 The Score. Follow him on Twitter @aharris670 and feel free to ask fantasy questions.