HOUSTON -- Former No. 1 overall Draft pick Mark Appel, fellow right-handed pitcher Vincent Velasquez and third baseman Rio Ruiz headline the Astros' contingent of prospects who will play in the Arizona Fall League this year. The rosters were unveiled Tuesday.
Joining Appel, Velasquez and Ruiz on the Salt River Rafters team are left-hander Mitch Lambson, right-hander Tyson Perez, catcher Tyler Heineman, infielder Joe Sclafani and outfielder Andrew Aplin. Sclafani is a member of the taxi squad, which means he's activated on only Wednesdays and Saturdays.
Appel is ranked by MLB.com as the team's No. 2 prospect, and he's No. 44 on the list of the game's Top 100 Prospects. Velasquez (eighth), Ruiz (ninth) are also ranked in the Top 20.
"We've got some of our top prospects that need some innings, and what better place to send them to Arizona to showcase their skill set while they continue to develop their talents," farm director Quinton McCracken said.
Appel, who missed all of Spring Training and the early part of 2014 while recovering from an appendectomy, struggled at Class A Lancaster (2-5, 9.74 ERA) before being moved up a month ago to Double-A Corpus Christi, where he's pitched better by going 1-2 with a 3.15 ERA in six starts.
On Tuesday night, Appel struck out 10 batters in eight-plus scoreless innings to lead Corpus Christi to a 1-0 victory against Frisco. He pitched into the ninth inning for the first time in his professional career.
"He has some innings left in him and we just want to see him pick up extra innings so he keeps that level of innings pitched on the year and continue his development as far as keeping the ball down in the zone and throwing strikes and continue with the momentum he's had in Double-A Corpus for us," McCracken said.
Ruiz, a fourth-round pick in 2012, was hitting .297 with a .389 on-base percentage, 11 homers and 73 RBIs for Lancaster. Velasquez, a second-round pick in 2010, is 7-2 with a 2.29 ERA in 13 games for Lancaster, allowing 31 hits, 19 walks and striking out 65 in 51 innings.
The Rafters, who will play home games at Salt River Fields in Scottsdale, include prospects from the Astros, D-backs, Marlins, Rockies and Twins. The six-team league, which is owned by Major League Baseball, begins play on Oct. 7.
Brian McTaggart is a reporter for MLB.com and writes an MLBlog, Tag's Lines. Follow @brianmctaggart on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.