Tyler Lyons stays in Cards' rotation, Michael Wacha optioned to AAA

Wacha's return to the minors will give him a chance to improve command of his fastball, Matheny said.

Star prospect Michael Wacha will return to AAA Memphis after an impressive stint with the Cardinals :: Jeff Zelevansky/Getty Images

Wacha's return to the minors will give him a chance to improve command of his fastball, Matheny said.