ALTOONA -- Pirates pitcher Charlie Morton returned to the mound Thursday in Altoona for his first rehab start since May 3, when he felt tightness in his shoulder and had to be removed from a Class AAA game at Lehigh Valley.
Morton, on a 30-day rehab program as he continues to recover from Tommy John ligament replacement surgery in June, threw four innings for the Curve against the Trenton Thunder and allowed two hits -- both home runs -- and only those two runs. He walked one and struck out one, with 40 of his 61 pitches for strikes.
He said he felt very good but won't know where he is at physically until Saturday when he is scheduled to throw again.
"I threw two really, really bad changeups that got hit," Morton said of the two home runs. "Other than that, everything was pretty good. My location was average, but the stuff was good, the two mistakes were bad. I would say the indicator [of whether his shoulder survives] would be, maybe when I throw my side [session] or maybe when I throw long toss, the day of my side.
"That's when I would be able to tell a little bit better."
Except for the two home-run pitches, Morton displayed great command and pitched well. He got eight ground-ball outs, which he said indicates his sinker was working well. There also were three flyouts and a strikeout in his four innings.
He said he mixed his pitches more than usual because he is trying to figure out what he can throw for strikes and how his shoulder handles all his pitches.
"Sinker, four-seam [fastball] and cutter, but mainly the four-seamer and the sinker, and I got the ground balls, which is what I was trying to do," Morton said of the pitches he used.
As for the two home-run pitches: "In those situations, I'm not sure how many changeups I'd even really be throwing but I am just trying to get a feel for where I am with my offspeed because at some point you have to break out the offspeed and challenge guys with that. You have to have secondary pitches."
Morton said he had no discomfort after throwing, which is welcome news.
Morton was pitching for Indianapolis, the Pirates' Class AAA team, May 3 when he said he felt his shoulder tighten before the third inning. He was shut down immediately.
That was his fourth rehab start, and he was hoping to make a couple in Indianapolis before joining the Pirates again.
"I know that guys coming back from Tommy John [surgery], there are sometimes bumps in the road, the shoulder tightness being one of those things," Morton said. "But I am 11 months post-op right now, and that's pretty good. This was definitely encouraging.
"The discomfort, soreness or stiffness was a little bit scary just because it has been a long time, it has been a long rehab, it is a long process. To come this far and have something happen, that would be very discouraging, so it was a scary occurrence, but today I felt good."
Morton, who last appeared for the Pirates May 29, 2012, against Cincinnati, said he will return to Pittsburgh and throw at PNC Park for a few days before rejoining Indianapolis and likely pitching Tuesday at Pawtucket.
Pirates manager Clint Hurdle said he was encouraged by the report he got about Morton, but said a lot of work needs to be done before the pitcher can return to the majors.
He said Morton will make at least three more rehab starts and stay on a five-day rotation, increasing his pitch/inning counts each start. Morton was limited Thursday to four innings and 65 pitches.
"He went four innings, 61 pitches, a little rough around the edges just because it was his first time back," Hurdle said of Morton.
"Velocity was 90 to 96 [mph], he threw some breaking balls and some changeups. All in all, it was a good effort. There is room for improvement.
"The five-day rotation I anticipate will stay on, but it will go from four [innings] and 65 [pitches] to five and 80, six and 90, seven and 100."
NOTES -- The Curve won, 6-2, but Morton did not factor in the decision. The game started at 10:30 a.m. on "Education Day," and most of the 6,855 in attendance were students from local elementary and junior high schools.
Paul Zeise: firstname.lastname@example.org and Twitter @paulzeise.