Mattheus hit Aaron Hill and walked John McDonald -- the only two batters he faced in an 8-1 loss to the D-backs -- and when his fastball was not in the mid-90s as it usually is, pitching coach Steve McCatty became concerned.
"I told the trainers and doctors I don't feel anything out of the ordinary," Mattheus said. "I don't feel any pain throwing. I don't have any answer for why it's not coming out."
Mattheus pitched three innings between his injury-shortened outings, walking only one. He actually felt tightness on Aug. 18, when he put up too much weight in the morning and had trouble getting loose.
"Tonight I didn't feel any of that," said Mattheus, who expects to get a few days off. "I felt [my velocity was down] a little bit in Spring Training, but I think that's just normal for Spring Training -- a little dead arm."