PHILADELPHIA -- Outfielder Kyle Tucker, who was activated from the disabled list Tuesday for Double-A Corpus Christi, has taken over the top spot as the Astros' top prospect by MLBPipeline.com. Tucker, one of five Astros on the Top 100 list, is ranked as the No. 10 prospect overall.
Tucker, 20, moves up one spot from the preseason rankings, taking the top spot from right-hander Francis Martes, who is in the Astros' bullpen. Tucker, who missed nine games for Corpus Christi with a back injury, was batting .294 with 56 runs, 22 doubles, five triples, 17 home runs, 63 RBIs and 19 steals in 84 games between Class A Advanced Buies Creek and Corpus Christi this year. With five players in the Top 100, the Astros came in sixth in the prospect rankings with 268 points. Points are awarded based on ranking, with the top-ranked player getting 100 points, the second-ranked player getting 99 points, etc.
Right-hander Forrest Whitley, the Astros' first-round pick a year ago, slides into the No. 2 spot on Houston's list, moving up three spots. He's ranked 40th overall. Fellow right-hander Franklin Perez moves up three spots as well at No. 3 and 46th overall. Outfielder Derek Fisher, who was called up to the Astros on Monday and started in center Tuesday in Philadelphia, remained fourth on Houston's list, and he is 54th overall.
The other Houston prospect in the Top 100 is right-hander J.B. Bukauskas, the Astros' first-round pick this year out of the University of North Carolina. He debuted on the list at No. 5 in the Astros' rankings and No. 87 overall.

The ranking of baseball's top prospects is done by MLBPipeline.com Draft and prospect experts Jonathan Mayo, Jim Callis and Mike Rosenbaum, who compile input from industry sources, including scouts and scouting directors. It is based on analysis of players' skill sets, upsides, proximity to the Majors and potential immediate impact to their teams. Only players with rookie status are eligible for the list. Players who were at least 23 years old when they signed and played in leagues deemed to be professional (Japan, Korea, Taiwan, Cuba) are not eligible.
The biggest movers on the Astros' list were infielder Colin Moran, who moved up 18 spots to seventh from 25th in the preseason. Moran will undergo surgery later this week in Houston to repair a fractured cheekbone after fouling a ball off his face Saturday in Baltimore. He could be out for the rest of the season.
Right-hander Hector Perez debuted at No. 13 on the list after not being ranked in the preseason.