Astros Prospect Primer: Springer waiting

Some players are on the verge of stardom, others are entering a crucial phase of their development and still others are getting their first tastes of full-season ball. With the 2014 season approaching, MiLB.com takes a look at the most intriguing prospects from each MLB organization.

Major League-ready: George Springer, OF

Last year, it was Wil Myers. This year, the poster child for delayed service time will be Springer.

MLB.com's No. 21 overall prospect famously chased the Minor League 40/40 club last season, when he slashed .303/.411/.600 with 37 homers and 45 stolen bases between Double-A Corpus Christi and Triple-A Oklahoma City. A call to the Majors, either last September or this Opening Day, seemed to be the next logical step. Neither came as the Astros hoped to keep Springer from making his Major League debut, therefore delaying his service time clock and his potential free agency by one year.

So Springer will bring his impressive combination of power and speed back to Triple-A to start the season. The biggest points of improvement for the UConn product will be his contact rate -- his 27.3 strikeout percentage in the Minors left something to be desired -- and a switch to right field, following Houston's offseason signing of Dexter Fowler.

"He's going to get more acclimated to right while he's there; that's going to be a big thing," Astros director of player development Quinton McCracken said. "He's also going to be trying to extend his at-bats a little, fight off the pitches he had difficulty getting to last year. The main thing is to get even more polished so he's ready to get going immediately when he gets to the Majors."

Shining star: Carlos Correa, SS

Though Springer will hit the big time sooner, Correa is undoubtedly the biggest name in the Astros system.

The 2012 No. 1 overall pick, who was taken one spot ahead of baseball's top overall prospect Byron Buxton, lived up to the hype in his first full season, slashing .320/.405/.467 with nine homers, three triples and 33 doubles for Class A Quad Cities.

The 19-year-old will make the jump to Class A Advanced Lancaster, where those numbers can expect some inflation in the hitter-happy California League. (Lancaster's The Hanger has the second-highest run and homer rates, according to MiLB.com's Ashley Marshall.)

Of course, Correa's numbers with the JetHawks should be taken with a grain of salt, but if he continues to show the 60 hit, 70 power and 70 arm grades MLB.com gave him this offseason, expect him to be at Corpus Christi before the season is out. The organization isn't to proclaim Correa's 2014 ascension to Double-A, but it is eager to see what its prized prospect can do in his second full year.

"He's going to make tremendous strides," said McCracken. "He's added 10 pounds of muscle this year and he just looks stronger. You can tell he's improved his plate discipline, too, when you watch him. Offensively, he'll make even more strides as far as driving the ball for power and average. He'll be stellar again."

Full-season debutant: Mark Appel, RHP

The Astros could have drafted Appel with that first overall pick in 2012 but chose the more signable Correa instead. Indeed, Appel didn't sign with the Pirates after being taken eighth, choosing to go back for his senior year at Stanford, and Houston was able to get its man a year later.

The 6-foot-5, 225-pound hurler enters his first full season of Minor League ball as MLB.com's No. 17 overall prospect, thanks to a fastball (70), slider (65) and changeup (55) that all rate above average. He showed good control (3.79 ERA, 1.18 WHIP, 2.13 BB/9) in a 38-inning stint between short-season Tri-City and Quad Cities last season, and the Astros have every expectation he'll carry that to Lancaster to start, even after a January appendectomy slightly delayed his start to the season. Given his advanced profile and college experience, Appel is a perfect candidate to move quickly through the system and, according to the team, how quickly he moves will be up to him.

"He'll let us know," McCracken said. "We don't want to get ahead of ourselves. We know he's going to be a top-of-the-rotation type guy for us, but for now, we need to let him go at his own pace. He'll get the ball every fourth or fifth day and he'll let us know when he's ready to move up to the next level."

More to keep an eye on: Jon Singleton has endured issues on and off the field over the last year. But if he shows signs that he can turn it around, the Major League first-base job could be his by midseason, with incumbent Jesus Guzman nothing more than a placeholder. ... Lance McCullers enjoyed a solid first full season at Quad Cities (3.18 ERA, 117 strikeouts, 104 2/3 IP) but may need to develop a better changeup if those numbers are to carry to the Cal League. ... Domingo Santana has hit at least 23 home runs in each of the past two seasons. He, Singleton and Springer should make for a scary RedHawks lineup. ... Delino DeShields, who was moved to second base after being drafted eighth overall in 2010, returns full-time to his old position in center field with Corpus Christi. The speedster batted .317 with an .873 OPS and 51 steals last year for Lancaster.