Martin has had two really awesome seasons (2012, 2016) where he rushed for over 1,400 yards, but has failed to make a dent in his four other seasons as a pro because of injuries, suspension, and poor play. Last season was one of the bad years, where he only appeared in 11 games and barely cracked 400 yards rushing (2.9 yards per carry on 138 attempts).
The Raiders' rushing attack wasn't all that great itself last season, with Marshawn Lynch leading the team in attempts (207), yards (891), and touchdowns (7). Since 2010, Oakland has had only two backs rush for 1,000 or more yards—Darren McFadden (2010 - 1,157 yards) and Latavius Murray (2015 - 1,066 yards). A fully healthy Martin could become the third, if given the majority of the carries.