For the outfield, it is a bit of a question mark as well. It is not officially known the defensive alignment but it is likely that Charlie Blackmon will slide over to left field, Ian Desmond will take over in center field, and David Dahl will take over in right field.
Blackmon saw his offensive production drop by nearly 30 percent from a 141 OPS+ to 115 OPS+ but his defense numbers plummeted from -5 DRS to -28, according to Baseball Reference, which was the worst in the entire sport last year. He will also see his salary jump from $12.5 million to $21.5 million in 2019 so the Rockies need him to put up numbers like he did in 2017.
Ian Desmond, unlike pretty much every other offensive free agent in Rockies history, has not hit as a Rookie. Among 332 qualifiers in baseball last year, he was 331st in launch angle, according to Baseball Savant. He did improve upon his 2017 season but still had an OPS+ 83, which is 17 percent below league average. Considering that he has only played 133 games in center field in his career and has below average defensive numbers there, it stands to reason that he may struggle defensively in center field, but not as much as Blackmon.
David Dahl will look to take a full-time role in right field for the Rockies in 2019 but the main concern is his injury history. When he plays, he has done well. If he played a full schedule in 2018, his pace would have put him at 34 home runs and 101 RBI (113 OPS+) but he only played in 74 MLB games, partially due to injuries and he also spent part of the season in Albuquerque.