TROY, N.Y. -- All the hype and expectations led up to this moment for Mark Appel. After four dominant seasons at Stanford, he arrived at the next level with the Astros organization, ready for his first step toward the Major Leagues with Class A Tri-City. With emotions and jitters flowing through him, he threw the fastball that's garnered him so much attention for his first pitch as a professional.

Lowell shortstop Tzu-Wei Lin turned on it, hitting it to deep center field for a leadoff triple.

"Welcome to pro ball, I guess," Appel said.

The No. 1 overall pick in the 2013 First-Year Player Draft made his pro debut with Houston's short-season affiliate Friday in front of 5,854 at Joseph L. Bruno Stadium. The 6-foot-5, 215-pound Appel threw two innings, giving up two runs (one earned) on three hits with no walks and a strikeout. With his workload closely monitored, Appel threw only 26 pitches.

Pitching coach Doug White said Appel is going to throw a bullpen session Sunday, with his next start scheduled for Tuesday against the Aberdeen IronBirds.

After Appel's greeting to the pros, though, ValleyCats manager Ed Romero said the rookie learned a valuable lesson.

"I think he battled. After the first pitch, I think he was in war," Romero said. "Basically, I think it's going to be something he's going to learn from. I think next time he'll be prepared."

In the first inning, though, Appel was hittable.

Lin scored on a grounder to short for Lowell's first run. Then Appel gave up a single and double to consecutive batters, and Lowell took a 2-0 lead. Tri-City ended up winning the game, 5-4, on a walk-off passed ball, long after Appel left the game.

Appel said he left a few fastballs, which topped out in the low 90s, up in the zone in the first, and Lowell's hitters took advantage.

White said with everything Appel's been through the past few weeks -- from striking out nine UCLA batters on May 24 in his last collegiate game to being drafted and making his pro debut -- the youngster was still trying to get back into a rhythm on the mound.

"I just think the first inning was more like he's in a spot and it's a new experience," White said. "All the eyes are on him. I don't think it was anything other than his fastball was up a little bit and he got hit just like anybody would at any point in their career."

Appel settled down and retired the next two hitters to get out of the first inning. He induced a grounder back to the mound, then struck Cleuluis Rondon out looking.

But Appel needed only seven pitches to induce three groundouts by the Spinners.

"I kept the ball down and I got them with my changeup pretty early in the count in the second inning," Appel said. "They swung at the pitches I wanted them to and got groundouts."

Appel could rapidly ascend through the Astros' organization and be pitching on a Major League mound soon. But even with so many young pitchers currently dominating hitters in the Majors, Appel said he doesn't have to fight the urge to excel as much as possible, as quickly as possible.

Right now, it's a day-by-day process of learning how to navigate pro lineups -- whether that's in Class A or the big leagues.

"Obviously the goal I have is to be in the Majors and be there as long as possible," the Houston native said. "Right now, this is what I needed. I think today was a success as far as what I needed to do."

Catcher Jake Rodriguez said he didn't need to say much to Appel before the game. Rodriguez attended Oregon State and played against Stanford in Pac-12 games, and said he knows Appel has a good mindset. He just told him to pound the zone.

"He did a great job getting in his routine, throwing strikes," Rodriguez said. "A couple things didn't go his way, but for the most part, he's right where I think he wants to be."

And now the debut is over and the jitters are gone. Now Appel just has to pitch.

"That stat line might not say so," Appel said, "but I know I'll have my next outing here, and then for the rest of the summer, I'll be able to get my work in and work toward that goal of making it toward the Majors."