Cubs manager David Ross compliments pitcher Caleb Kilian’s growth

John Antonoff/For the Sun-Times

The Cubs’ Caleb Kilian throws a pitch during a spring training game in Scottsdale, Arizona, last month.MESA, Ariz. — When rookie pitchers Caleb Kilian, Javier Assad and Hayden Wesneski made their debuts last year, the Cubs didn’t know exactly how each of them would handle the jump. Now, they’re part of the team’s improved starting depth.

Assad and Wesneski are competing for the fifth-starter spot. And Kilian, who held the Reds to one run through three innings Wednesday, is expected to serve as an option to be called up from Triple-A.

“The confidence has continued to build,” manager David Ross said of Kilian, referencing his bullpens and a game on the backfields.…