Some long teeth in NFC West backfields

Roughly 90 percent of currently signed NFL halfbacks are not yet 28 years old.

I'm counting one, Fred Jackson, older than 30. (He is 31.) Willis McGahee and Michael Turner are 30. The rest are younger.

Teams will add a few older backs as the draft and training camps approach, but the NFL is a young man's game, particularly at halfback (as opposed to fullback).

The San Francisco 49ers' agreement with Brandon Jacobs, 29, gives the NFC West four of the 11 oldest halfbacks in the NFL. Leon Washington is also 29. Frank Gore and Steven Jackson turn 29 this year.

I touched on that issue, the Arizona Cardinals' young backs and the 49ers' potential thinking on Jacobs -- all in the video above.