Mark Appel was the first overall pick in the 2013 draft. But the righthanded pitcher rarely performed like a premier prospect in his three seasons with Houston's minor-league system.

The 24-year-old had a 5.12 ERA in 253 minor-league innings as he seemed to struggle with the expectations that came with being the No. 1 pick. The Phillies, who acquired Appel on Saturday as part of the Ken Giles trade, hope a change can help Appel return to top form.

"Expectations in this game are real and pressures in this game are real and sometimes there are good reasons for it and sometimes not. Sometimes, a change of scenery can really help players," general manager Matt Klentak said Monday. "Now we have to do our part to help him change that scenery as well. It's not a matter of just changing uniforms. We are going to have to put him in a good environment and help him do things that will have him reach his ceiling."

Along with Appel, the Phillies acquired righthanders Harold Arauz, Vincent Velasquez, and Thomas Eshelman plus lefthander Brett Oberholtzer for Giles and 17-year-old shortstop Jonathan Arauz. Velasquez, 23, and Oberholtzer, 26, will compete for spots in the starting rotation. Eshelman, 21, and Harold Arauz, 20, will start 2016 in the minors.

Klentak said Appel would likely be invited to major-league spring training. Appel was promoted to triple A in June and made 12 starts. His lack of seasoning could cause the Phillies to stash him at triple-A Lehigh Valley until midseason. If so, he would have the chance to work with IronPigs pitching coach Dave Lundquist, who was promoted this winter from double-A Reading. Lundquist has been praised by the organization's pitchers.

Appel had a 4.48 ERA in 681/3 innings with triple-A Fresno. He struck out 61 batters and walked 28. He finished the season by pitching at least six innings and allowing three runs or fewer in each of his final three starts. Appel, who pairs his high-90s fastball with a slider and splitter, averaged six strikeouts per game during that stretch.

"Mark has carried a lot of expectations on his back over the last few years. But we want to appreciate what he's done," Klentak said. "He's gone out and reached triple A, he still possesses really good stuff and he's still young. And that's exciting for us as we build a pitching staff and a team moving forward. We believe Mark Appel is going to fit right in with what we're trying to do."