Running backs who turn 30 leave fantasy football owners feeling sick with apprehension. In reality, 30 is a very young age. It’s when most people start leaning away from their childlike side and find themselves focusing more on adulthood. By the time you’ve reached 30 in the NFL, you’re thought of as a grandpa, an old timer whose years left are limited. In 2018, three [possible] starting running backs, Bilal Powell, DeMarco Murray, and LeSean McCoy, will be eclipsing the dreaded 30-year mark. Looking back on 2017, McCoy was the only one of those three to eclipse 1,000 rushing yards (1,138). Both Powell (772) and Murray (659) were mediocre running backs when it came to fantasy value. Not one running back who was 30 or older in 2017 reached 1,000 yards. The closest was 34-year-old Frank Gore, who finished mere yards away (961). The two 31-year-olds, Marshawn Lynch and LeGarrette Blount, both finished under 900 yards, and 30-year-old Jonathan Stewart finished under 700 yards. Now let’s dive a little deeper into these players’ 2017 seasons and try to figure out where we would be taking them in 2018 fantasy drafts. DeMarco Murray – Tennessee Titans   It is interesting trying…