The Astros' No. 2 prospect, Appel threw in the bullpen early Sunday while being watched by farm director Quinton McCracken and pitching coach Brent Strom before heading to Corpus Christi. He was in and out of the ballpark before most players knew he had been there.
"As far as I know, nobody had a problem with Mark coming here and throwing on his way to Corpus, on his bullpen day," Castro said. "It's pretty much what it boils down to. It pretty much is a non-issue for everyone here. On a personal note, I'm happy for him that he's moving on up and getting out of Lancaster and going to Corpus, and hopefully he has success there. There are no feelings of ill will or anything like that in the clubhouse here toward him or anything like that. I wanted to clear that up."
In fact, Castro sent a text message to Appel later Sunday after a report surfaced claiming that players, who spoke anonymously, weren't happy with Appel's appearance at the ballpark. Castro and Appel are both Stanford graduates, so they communicate frequently.
"I wanted to give him a heads up just to make sure he's not reading stuff and thinking guys are upset with him for, really, something that no one should be upset about," Castro said. "It wasn't something that really should have left the clubhouse. It really started as a joke and kind of got blown out of proportion a little bit. I wanted to make sure there were no misunderstandings going on and everybody was on the same page. It was a non-issue."
Qualls said he was glad Appel was doing what he needed to do to try to get better and said that Appel was welcome at the ballpark.
"If it's a step toward him getting to the big leagues, I'm all for it," Qualls said. "He's a first-round pick, and obviously they wanted to see him throw. More power to him. I don't think anybody is too worried about what's going on down in the Minor League system. I think everything kind of got blown out of proportion.
"We all like Mark. I had him as my locker mate in Spring Training, and I even told Castro to text him and tell him, 'Everything is fine up here; keep doing what you need to do to get better and get up here. That's the ultimate goal -- to get to the big leagues.' Everything kind of got blown out of proportion. Who knows?"
The Astros moved Appel to Double-A to get him out of the hitter-friendly environment in Lancaster. He went 2-5 with a 9.74 ERA in 12 starts for the JetHawks but posted his first quality start on Thursday, allowing five hits and two runs while striking out seven batters in six innings at Stockton. The Astros' goal for Appel was to have him pitch a bulk of the season at Corpus Christi, but that was before he missed Spring Training due to an appendectomy.
Brian McTaggart is a reporter for MLB.com and writes an MLBlog, Tag's Lines. Follow @brianmctaggart on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.