Ravens struggling at run blocking

For most of the offseason, the top storylines for the Baltimore Ravens' offensive line have been about the preseason battle at center and Marshal Yanda's recovery from shoulder surgery. But the biggest development in the preseason has been the poor run blocking by the Ravens' starting offensive line.

Five linemen who have started for the Ravens this preseason have received negative run grades from Pro Football Focus: left guard Kelechi Osemele; centers Gino Gradkowski and A.Q. Shipley; right guard Jah Reid; and right tackle Michael Oher. It's the primary reason running back Ray Rice has averaged 2.9 yards per carry in three preseason games. At times, it's been difficult for Rice to reach the line of scrimmage without getting hit.

The lineman who has struggled the most is Osemele, whose minus-6.8 run block grade is the lowest for all guards this preseason. The next lowest-rated guard is the San Francisco 49ers' Al Netter, and he was cut three days ago.

Osemele is the Ravens' most promising young offensive lineman. He's smart, athletic and versatile. Last season, Osemele became the first rookie to start a full season on the Ravens' offensive line, starting all 16 regular-season games at right tackle before moving to left guard in the postseason. Pro Football Focus gave Osemele a positive run blocking grade last season, but he ranked 30th among tackles in that category.

Excluding Yanda, who played one quarter this preseason, the only starting offensive lineman for the Ravens who received a positive run grade this preseason is left tackle Bryant McKinnie, who ranked fourth among tackles.