By Bruce Levine-

(CBS) — The next wave of Cubs prospects to get the call after the promotion of Javier Baez hasn’t been etched in stone as of yet.

Jorge Soler and Kris Bryant are hammering their way through Chicago’s farm system in preparation to launch their big league careers. Good numbers and other variables will determine who arrives and when that might be.

Soler appears to be the next touted player the Cubs will promote. The organization’s player of the month for April, Soler was hitting .369 with 11 home runs and 40 RBIs in 43 games (combined Double-A and Triple-A) and only needs to stay healthy in order to matriculate to the friendly confines of Wrigley Field.

Cubs management has a plan in place to move the next wave of young farm hands along.

“It has always been our goal to vertically integrate the entire system,” president of baseball operations Theo Epstein said Friday. “When you have home-grown players that you can promote, it does wonders for that. It boosts moral for our minor league players. They can look and see guys that they were playing with on TV. It is great for our staff as well to get a sense of pride with these promotions.”

Soler is under contract for nine years and $30 million. He is already on the 40-man roster, so a September call-up will be a mere formality. Bryant, who just completed one year of professional baseball, is another issue altogether.

Epstein has said all season that a major league call-up for the 22-year-old third baseman wasn’t in the cards.

“Nothing has changed,” Epstein said. “I still don’t foresee Kris getting called up this year. It is his first full professional season.”

What the Cubs won’t say publicly is that agent Scott Boras, who represents Bryant, doesn’t let his star players sign an early long-term deals. Knowing a long-term contract will most likely not occur would make any baseball executives hesitate to start the major-league free agent clock on any top young minor league player.

Bryant has been a dominant hitter at both Double-A and Triple-A, hitting .341 with 37 home runs and 95 RBIs combined at the two levels this season. His defense has improved due to the extra time he puts in on drills before his team takes batting practice.

“He has a chance to be a 10-time  All-Star,” said a top scout from the American League. “He has the work ethic and the tools to be a great player .”

A September call-up would be the most likely call on Soler.

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