"We've been certain in our minds for a while he was going to be a September call-up," Epstein said Wednesday. "The key to the decision to bring up Soler is he was going to be a call-up for us mainly because he needs the at-bats."
The Iowa Cubs aren't looking like a playoff team, and their regular season ends Monday, so Soler will get the extra at-bats in the majors. He'll make his debut batting fifth and playing right field Wednesday against the Cincinnati Reds.
Soler hurt both his hamstrings earlier this season, forcing him to miss all of April and most of May. When he finally got healthy -- thanks in part to some dramatic work by the training staff -- Soler vowed to impress.
"The turning point for Jorge was how he handled the second hamstring injury," Epstein said. "Instead of getting really down on himself and pouting, he really embraced that adversity as an opportunity to get better. At the same time, he was watching what Javier [Baez] and Kris Bryant were doing. We got the sense he wanted to catch up a little bit, as well.
"He communicated he was on a mission."
Soler caught up quickly. He hit .340 with 15 home runs and 57 RBIs in 62 games in the minors, putting himself in a position for the promotion. His plate discipline continues to be his strength, as his walk totals are more in line with a veteran hitter. His on-base percentage this season is .432. That's partly what makes him unique. That, and his physical presence.
"He was born with a very advanced approach at the plate," Epstein said. "The first things fans will notice is how impressive he is physically. He's put together like an NFL player."
A 6-foot-4, 215-pound, 22-year-old power hitter who can handle the strike zone doesn't come along very often. It's one reason the Cubs extended a nine-year, $30 million contract to him back in 2012.
"All things being equal, we prefer our higher profile prospects to break in on the road where they can just play and keep distractions to a minimum," Epstein said. "He's made tremendous strides with his swing mechanics and swing path. ... His ground balls have become line drives. His line drives have become fly balls. His fly balls tend to leave the ballpark."
Soler's promotion would never have happened without him getting healthy. After his second hamstring injury, the Cubs grew concerned there might be something chronic going on. They did a full body work-up.
"He had a disproportionate amount of his muscle mass located on the front of his body, and that was creating some inequalities and putting extra strain on his hamstrings when he made some athletic movements," Epstein said. "The training staff has tried to redistribute some of that muscle mass, make him more balanced between his anterior and posterior sides."
That's when Soler put it on himself to show the world why the Cubs had invested so much in him. Now he'll join former Iowa Cubs such as Baez and Arismendy Alcantara for a 4 ½-week learning experience.
"This is the right time to bring him up here," Epstein said.