Petrick, 24, has been plagued this season by shoulder soreness. He pitched to only one batter in big league spring training in March. He is listed on the disabled list at Class AAA Iowa and will rejoin the team later this month if all goes as planned.
Petrick said last week that he'd tinkered with his mechanics in Arizona.
"My pitches weren't coming out of my hand very well," he said. "I was cutting the ball off. I worked on some easier mechanics to throw harder and with easier motions."
Joining Petrick in Daytona is Grant Johnson, who had been dealing with elbow discomfort this spring. A season ago, the right-hander appeared in 44 games between Daytona and Class AA Tennessee, going 2-2 with a 4.11 ERA.
Johnson, who turns 25 later this month, was the Cubs' first selection (66th overall) in the 2004 draft from Notre Dame.
At Tennessee, right-hander Jim Henderson (back injury) was activated from the disabled list Monday. Henderson, 25, made 50 appearances a season ago – the bulk of which came at Tennessee, where he was 4-3 with a 1.86 ERA in 58 innings.