Bruce Chen ready for rehab assignment as Royals keep mum on his role

More than a month after he last pitched in a game, Royals veteran Bruce Chen is finally preparing to leave the club on a minor-league rehabilitation assignment.

Chen (bulging disk in lower back) is expected to head to the minors after a bullpen session on Sunday. He threw a pair of 15-pitch simulated innings against live batters on Friday afternoon.

Manager Ned Yost continues to play coy about Chen’s role upon his return. "Let him come back first," Yost said. "Then we’ll decide."

The team still intends to stretch Chen (1-2, 7.45) out as a starter. He should throw about 45 pitches in his first rehab appearance. He can accumulate 90 to 100 by his third start.

His competition on Friday included backups Brett Hayes and Jimmy Paredes, plus pitchers James Shields and Danny Duffy.

"He humbled Duffy," Yost said. "Duffy thought he was a good hitter. Until he faced Bruce. He walked out a little defeated."

To reach Andy McCullough, call 816-234-4370 or send email to rmccullough@kcstar.com. Follow him on Twitter: @McCulloughStar.