Each and every year, the same lesson is hammered home about backs in this league: Run them to death and then discard them like an old pair of underwear.
Portis missed 19 games the past two seasons as injuries kept him off the field. But he's also 29 years old, which means 30 is coming.
That's a magic number for backs. Few of them can still play at a high level at that age.
Portis was scheduled to make $8.2 million this coming season. But don't think money was the main issue. If he could still run for 1,5000 yards, he gets it.
We know better.
Backs break down quickly.
That's why teams run them to death and then send them into retirement.