The Bears rookie running back rushed 7 times for 39 yards, which comes to an average of 5.6 yards per carry. That is far above Anthony Thomas' 3.4 average before he was placed on injured reserve.
Leon Johnson had a decent game against the Jets, but in the end like Thomas averaged less than 4 yards per carry on 15 rushes. Take away his 23-yard run and he averaged 2.4 yards on 14 attempts.
There is serious doubt rather or not Thomas can be an every down back and Johnson is a career backup, so it's time to give Peterson a shot.
However, the coaching staff might hesitate to give Peterson more than the occasional serious because if he succeeds it would bring the question, why didn't he see more action earlier in the season.
Of course, there's a chance Peterson won't be any more productive than Thomas or Johnson, but it's time to find out. Because if Peterson doesn't show something then the Bears might need to add running back to their draft list.