Charlie Blackmon would hit third for the Rockies.
Hitting third would be Charlie Blackmon and he would be the designated hitter. Even though Blackmon has stated his disdain for the DH, of the Rockies outfielders, he is the worst defensively (-39 fDRS in the past three seasons) so that’s why he would DH. If the NL doesn’t have the DH, he would play right field and the Rockies’ outfield defensive alignment would have to change.
Blackmon started 2020 off on a terror as he was hitting .500/.527/.721 in the Rockies’ first 17 games but like the Rockies for the last three-quarters of the season, he fell off a cliff. He hit .216/.283/.327 to make his season total slash line .303/.356/.448 with an OPS+ of 103 (wRC+ of 97, so, essentially, league average).
If the DH is a permanent fixture in the NL, the Rockies will likely rotate several players through the position as a “half-day off” but Blackmon should be the primary player in this role.