I want to revisit the issue of numbers. You sign a guy expecting him to play 16 games. You pay him to play 16 games. You always know there's an opportunity for injury, but these guys are signing 16 game contracts. Agents wouldn't accept negotiations any other way.
So, McCoy's value of 4.88% is assuming he plays 16 games. Some funny math here, but stay with me. His yards from scrimmage, extrapolated to 16 games is 1,519.36.
We can assume there would have been a bump in the team's total yards. So if we factor in his difference (a feature back @ 94.96 yards from scrimmage/game) in the four games he missed in their entirety, the team's total yards for year would have been 145.84 yards higher or 5920.84 yards.
Which means, extrapolated over 16 games, McCoy would have been paid 4.88% to account for 25.6% of the team's total yards from scrimmage. Is THAT worth it? (on what planet is it not?)