Martin found the end zone this week for only the 2nd time in 2 years, so it looks like he has reached his ceiling and it's time to sell high if you can. I recommend selling for whatever you can get at this point. Maybe you can convince someone he has started to turn it around.
He does play New Orleans this coming week, who let Murray run for 149 yards (6.2 ypc) and 2 TDs. I'd say hold for at least another week.
He also has a game vs Green Bay (32nd vs the run) on championship weekend, and other games vs
Carolina (27th), Chicago (20th), Atlanta (28th) and Cleveland (29th). So about half of his matchups the rest of the season are very favorable.
I also like that he got 16 touches to Rainey's 5.