Cubs right-hander Yu Darvish lasted just one inning in his rehab start with Class A South Bend on Sunday, casting doubt on his availability for the rest of the year.

Darvish, who has been sidelined by triceps and elbow injuries, shook his arm as he left the field after striking out Great Lakes' Romer Cuadrado with a 95 mph fastball for the last out of the first. But he said the first inning was great.

"I felt real good,'' Darvish said through an interpreter. "I didn't feel any abnormalities in that sense.''