Dahl spent the first four months playing for the Hartford Yard Goats, nomads of the Double-A Eastern League because the team's park was not and would not be completed. It meant constant road trips and irregular meals. At times, he picked not eating over grabbing another bag of fast food.
But having spent the offseason in Houston, Dahl has regained weight and strength, which he will need as he competes with veteran Gerardo Parra for the Rockies' left-field job.
"I ended the season at 180 [pounds] and now I'm 198, last time I weighed. I'm not trying to put on a ton of weight," said the 6-foot-2 Dahl, who was called up July 25 and tied a record set by the Reds' Chuck Aleno in 1941 by hitting in his first 17 Major League games. "I'm just getting my meals in, working out, doing what I need to do.
"I went in just wanting to get stronger, working out, getting some of the weight that I lost back on and just working on some things with my swing -- pitch selection, things like that -- where I feel I can get better."
Dahl, the Rockies' first-round pick, 10th overall, in 2012 out of Oak Mountain High School in Birmingham, Ala., spent the offseason in Houston for workouts at Dynamic Sports Training, where he worked with players such as young Astros star infielders Carlos Correa and Alex Bregman. He also worked with noted hitting instructor Matt Pierce, the head coach at Houston Christian High School.
Dahl was not looking for major changes to his approach, just better pitch selection.
New Rockies hitting coach Duane Espy, familiar with Dahl in his former job as the club's Minor League hitting coordinator, saw Dahl for five days in December and assessed his offseason plan as sound. Even though he has increased his weight, Dahl doesn't look as if he's muscled up to the point that he loses his natural swing mechanics.
"There are two ways to move a baseball," Espy said. "One of them is with leverage and maybe a little more the strength-muscle aspect of it, and there is moving the bat very rapidly. Even though, size-wise, it doesn't look like it, he generates a lot of bat speed, and that moves the baseball just as well as those big muscles do."
Being stronger and more selective could make him dangerous. According to Statcast™, Dahl's average exit velocity on his 135 batted balls was 88.02 mph -- a figure that was better than anyone who had at least 300 batted balls. Obviously, more balls in play would mean more chances for softer contact that could bring down the average, but Dahl has the chance to hit balls as hard as anyone in the game.
"I really didn't have any expectations going up there," Dahl said. "At the time, we were in the Wild Card race. I just wanted to go up and help the team win."
How Dahl will contribute this season will be one of the key issues to watch this spring.
The Rockies signed Parra last winter for three years at $27.5 million, but he struggled with consistency, then missed 46 games with a left ankle injury and limped to the finish while playing more first base than outfield. But Parra (.253/.271/.399 in 102 games last year) is healthy and hopes to be in game shape sooner than usual by playing for Venezuela in the World Baseball Classic.
The Rockies have invested quite a bit in both players. Parra has a sizable contract, but Dahl was a top 10 pick who received a $2.6 million bonus and plenty of time and effort by the team's player development component. So it should be simple competition for the starting role, with prospect Raimel Tapia and non-roster veteran Chris Denorfia in the mix.
"It's something I'm not really thinking about," Dahl said. "We have a bunch of great outfielders. Everyone wants to go out and win a spot, and that's something I'm not really going to think about or talk about. I'm going to go out and play and help the team in every way I can."