KISSIMMEE, Fla. (AP) -- Stray pen marks covered the hands of Mark Appel, a bead of sweat dripped off the end of his nose and more sweat trickled down both of his arms.
Last year's top overall pick threw for the first time on Thursday since an emergency appendectomy last month, but that didn't stop the Houston starter from taking time to sign an autograph for each of the dozens of fans who asked for his signature as he left the field.
After three straight 100-loss seasons, Appel and other up-and-coming prospects have infused this team with optimism. And, as one of the future faces of the franchise, Appel is more than happy to work both on and off the field to be the kind of player worthy of such a tag.
''We want to be successful at the major league level, we want to be in the playoffs year in and year out and we want to win a World Series,'' said Appel, who threw a 22-pitch bullpen session Thursday. ''Any way I can be a part of that, that's what I'm here for.''
The polished Appel made 10 starts between Tri-City and Low-A Quad-Cities last season and could be on a fast track to the majors, though it's unlikely that he'll be in Houston before 2015.
But he's just one of several youngsters who have helped Houston's minor league system rank as one of the best in baseball. Outfielder George Springer and first baseman Jonathan Singleton could both be ready this season, which would be a boost to a team that lost a franchise-record 111 games last season.
Springer hit 37 homers and 108 RBIs with 45 stolen bases combined in Double-A and Triple-A last year. Singleton, who has been ranked as the top first-base prospect in baseball, looks to rebound from a tough 2013 when he served a 50-game drug suspension.
''He's coming in to compete for the starting first base job,'' manager Bo Porter said. ''He's an obvious talent. He's one of our top prospects and we believe that he has the opportunity to be an impact player for many years to come for the Houston Astros.''
Singleton admitted he was nervous before the first full-squad workout and said he can't help but think of the possibility of making the big league team this season.
''That's always a thought in my mind, but the biggest thing I focus on is playing ball and having fun,'' he said. ''Everything else you can't control, so I just try to control what I can control.''
Another faucet of Houston's improvement is that the Astros think the young guys who got their first major league experience last year will be much better, too. Porter also believes the revamped bullpen will help get things on track.
''It's our goal to be the most improved team in major league baseball (and) I believe ... we have the group together and we can actually accomplish that,'' Porter said.
One of the biggest problems for the Astros last season was a bullpen that blew 29 saves. They addressed the issue with the signing of Jesse Crain, who was an All-Star last season and had a 0.74 ERA in 37 appearances for the White Sox. Other upgrades to the group include veteran Chad Qualls and Matt Albers.
''It can be frustrating to be winning the whole game and then lose, especially if they did it that many times,'' Crain said. ''Hopefully me and the other guys that they brought in there can help strengthen that and a lot of those games that they lost last year we can win this year and have a quick turnaround.''
Catcher Jason Castro was Houston's All-Star in 2013 after his best season where he hit .276 with 18 homers and 56 RBIs. He acknowledged that the last couple of years have been difficult to deal with, but now he feels like there's finally a light at the end of the tunnel.
''The last few years have been the steps necessary to get to where we want to go and now we're kind of on the upswing of things,'' Castro said. ''I don't think we're going to be like we were in the past. Just with the additions we've made already, let alone the guys coming up in the minor leagues, we're going to see some pretty significant improvements on the field and sustained ones for the years to come.''