The development of another Phillies prospect brought Aaron Altherr to his parents' house in suburban Phoenix this past fall. The 22-year-old outfielder is 6-foot-5, glides to the ball, and looks like a future major-leaguer. He commuted to the ballpark every day for Arizona Fall League ball, a showcase league.

One morning last month, Delino DeShields Jr., a Peoria Javelinas teammate, pretended to dribble a baseball like a basketball before another sleepy batting practice. Altherr, who received scholarship offers to play basketball at Division I schools, put his arms up to defend. DeShields tossed the baseball in the sky. Altherr snagged it.

Altherr embodies an organizational philosophy. The Phillies value athleticism in their position players, almost to a fault. They prospered with patience for Domonic Brown. But they have failed to develop another everyday player since Michael Bourn was picked in 2003.

The next potential wave of outfielders will play at double-A Reading in 2014. Altherr will be there, probably in center, with Kelly Dugan and Zach Collier in the corners. All three are "high-ceiling" talents with uncertain futures. Dugan and Collier were top picks in 2009 and 2008, respectively.

Next season will determine if any of them offer real promise.

"I'm definitely looking forward to it, playing there, especially in a smaller ballpark," Altherr said. "Hopefully, I can put up some numbers there."

The Phillies added Altherr and Dugan to their 40-man roster last month to protect them from selection in the Rule 5 draft. Baseball America ranked Altherr as the team's No. 9 prospect and the system's best defensive outfielder. That, of course, guarantees nothing.

Altherr has the typical promises and shortcomings of a "high-ceiling" prospect. His power stroke is developing with age; his slugging percentage increased by 116 points from 2011 to 2013. He whiffs too much; 140 strikeouts ranked third in the Florida State League. He has averaged 28 stolen bases over the last three seasons.

After a .792 OPS during a full season at single-A Clearwater, he strives for improved plate discipline.

"That's pretty much it," Altherr said. "I feel like if I cut down on the strikeouts, my average will go up, all my other numbers will go up. I just have to get those down. I need a better selection at the plate."

Said fellow prospect and fall-league teammate Cameron Rupp: "He has everything it takes."

Dugan and Collier experienced mixed results in 2013. Dugan, 23, jumped to Reading after a hot first half in Clearwater. He played 56 games and hit 10 homers and 12 doubles at each level. But his batting average and on-base percentage plummeted.

Collier, 23, was added to the 40-man roster last winter following a strong Arizona Fall League performance. He responded in 2013 with a disappointing .658 OPS at Reading. He struck out 129 times in 123 games.

The Eastern League tends to separate the players with tools from the more polished ones. Altherr, Dugan and Collier need not look far for a cautionary tale. Anthony Hewitt, the Phillies' first-round pick in 2008, has failed to establish any prospect status. Hewitt, another so-called "high-ceiling" player, has a career .271 on-base percentage in the minors and has never gone above .300 in a season. He enjoyed an uptick in power while at Reading last season, but that is typical because of the smaller dimensions at FirstEnergy Park. His strikeouts - 144 per season since 2010 - could ultimately be his demise.

The Phillies' first-round pick with the most major-league experience since Cole Hamels was drafted in 2002 is Adrian Cardenas, who retired after the 2012 season. He played in 45 games with the Cubs and batted .183. The second round is just as bare; no player has developed into a regular since Randy Wolf, who was drafted in 1997. Anthony Gose, now with Toronto, has the best chance.

Cody Asche, a fourth-round pick, could be the next everyday player to emerge from the Phillies' system. He was a fast riser in the minors because of his three years at college. Third baseman Maikel Franco, signed for $100,00 from the Dominican Republic, is the organization's top prospect.

And in Reading, eyes will be on three outfielders with unwritten futures. A sprained wrist hampered Altherr during Arizona Fall League play. He hit .200 in 45 at-bats. He relished the peek at what it will take to succeed.

"This is what I'm going to be seeing the next few years," Altherr said, "so I better get used to that."