Michael Turner had a rough four weeks.

After the first four weeks of the season, Turner led all runningbacks with 73.3 fantasy points in a standard scoring league (1 point per 10 yards rushing/receiving, 6 points per touchdown, -2 points per turnover). But in his last four weeks, Turner has mustered only 29.3 total points, an average of about 7.4 per game.

That total dropped Atlanta’s top back from No. 1 to No. 6 overall at the season’s halfway point.

Clinton Portis, meanwhile, climbed nine spots in the rankings over the last four weeks to claim the top spot. He had 58.5 points at the quarter pole, but has scored a whopping 83.6 points in the last four weeks. Portis does have a bye in week 10 which could set him back during the next quarter, but has pulled away from the pack by almost 20 points at midseason.

Frank Gore and Marion Barber swapped spots in the updated rankings. Gore, ranked No. 2 four weeks ago, slipped to No. 3 having scored 53.5 points over the last four weeks. Barber, previously ranked third, overtook Gore’s No. 2 ranking with 57.8 points in the last four.

Staying power

Several backs remain solids RB1s at the midseason point. Though they have shifted order over the past four weeks, all of the following backs remain in the top-12: Matt Forte, LaDainian Tomlinson, Chris Johnson, Ronnie Brown, Adrian Peterson and Marshawn Lynch.

Can the rookies Forte and Johnson avoid the rookie wall to stay among the elite backs of the NFL the rest of the way? It will be interesting to see what happens with these two.

Two newcomers

Surprisingly, the two newcomers to the midseason class of RB1s are old timers on this list. Brian Westbrook and Steven Jackson appear in the top-12 for the first time this season after a few stellar recent performances.

And the two back they replaced: Reggie Bush and Larry Johnson. Most fantasy experts did not expect Bush to remain an RB1 the rest of the season, but he was unfairly set aside by a knee injury. While he may be able to regain RB1 status by season’s end, that seems unlikely now. LJ, meanwhile, is battling a multitude of legal issues off the field and may not see action for a few weeks. It would take a miracle for Johnson to finish the season as an RB2.