Chen pitched two innings for Double-A Northwest Arkansas, giving up four earned runs on five hits in the first game of a doubleheader against Arkansas at Little Rock. He walked none and struck out two, tossing 45 pitches (29 strikes) against the Angels' farm club.
Right-hander Kyle Davies, also on the disabled list, started the second game and pitched two-plus innings. He also gave up four runs, but just two were earned, on five hits. He walked none and struck out three, using 58 pitches (38 strikes).
Royals manager Ned Yost expects Chen and Davies to each make one more start in the Minors and throw 60 to 70 pitches.
"Then they'll be ready to go 80 to 90 and I can take that at the big league level. If I can take them to 80 pitches, I'd rather have them pitching here than another rehab start," Yost said. "This whole mess started with both of those guys going down and I want to get them back in."