He opened the season with 24 disposals in a victory over in round 1 before spending a night in hospital in the lead up to round 2 as the result of a severe migraine. Cotchin recovered fully overnight and traveled with the team to play against Adelaide in what would be the 200th match of his career. The following week he received a maximum 10 Coaches Association Award votes as the coaches' unanimous best-on-ground following 31 disposals and six tackles in a win over . Cotchin repeated the effort in round 6, earning 10 votes after recording a game high 18 contested possessions and 29 disposals in a win over . He suffered a minor knock to his left knee during a collision with a goal post during that win however and was considered in some doubt for the club's match against the following week. He was named to play in that match during team announcements, but was a late withdrawal just before game was due to begin. It was his first match missed through injury since May 2016. Cotchin's absence was contained to one match, making a return against in round 8 where he was exceptional, recording 22 contested possessions to equal the second-most in a match by any Richmond player in club history. To that point he had recorded the equal-fifth most votes (37) in the AFL Coaches Association's champion player of the year award. After an impressive 32 disposals, nine clearances and eight score involvements against in round 10, 3AW commentator Tim Lane labelled Cotchin "the best player in the game" following a superb stretch of form from round 6 onward in particular. At the half-way point of the season Cotchin was named in "AFL Media" and "Fox Footy's" mid-year All Australian squads while also being named in the "Herald Sun's" team of 22 players. Cotchin had a significantly reduced impact statistically in the second half of the season, recording more than 20 disposals only twice in the final 11 weeks of the regular season. His defensive work was impressive though, including when he recorded a game high nine tackles and the highest pressure point count of any player in the league in round 20. A minor hamstring injury in round 21 saw Cotchin play significantly reduced minutes in that match and miss the entirety of the club's round 22 win over . He returned for the final match of the home and away season in round 23, recording 17 disposals in a win over the . At that time, Cotchin was named in the 40-man squad but went ultimately unselected for the All-Australian team.