The batters he was tasked to face included Addison Russell, Dexter Fowler and Kris Bryant.
"I guess these aren't high school hitters," Murphy said after the game.
After an error, a walk, a single and a hit batsmen, Murphy had loaded the bases for Bryant, the 23-year-old wunderkind. It went about as well as expected.
Murphy missed badly on a high pitch to fall behind 1-0, then saw Bryant foul off a 79-mph "fastball" and crush a 1-1 pitch for his first career grand slam, giving the Cubs a 17-0 lead.