A's prospect A.J. Griffin struck out seven over seven strong innings and Jeremy Barfield extended his hitting streak to 12 games as Double-A Midland held off Corpus Christi, 3-2, on Wednesday afternoon.

Griffin, the A's No. 13 prospect, who led Oakland's Minor League system in strikeouts last season, remained undefeated en route to winning his third straight start. He held the Hooks to one run on three hits, a homer by Jose Martinez in the fifth inning, while adding to his stellar strikeout numbers.

Griffin has whiffed 41 batters and walked just five in 37 1/3 innings for the RockHounds over six starts. He's held opponents to two earned runs or fewer in every outing, giving him a 1.93 ERA.

Barfield, who's father and brother both spent time in the Majors, went 2-for-5 with a two-run double in the third to break a scoreless tie. He's hit safely in his last 12 games and has eight RBIs in his last seven starts.

Converted pitcher and 2007 first-round pick Sean Doolittle relieved Griffin in the eighth and faced three batters -- the former first baseman walked Jair Fernandez and beaned Jonathan Villar before getting Andrew Simunic to hit into a fielder's choice, ending his second Double-A outing as a pitcher. James Simmons came on with runners at the corners and worked out of trouble to preserve the Midland's 3-1 edge.

Jarred Cosart, the Astros' top pitching prospect, started for Corpus Christi and was charged with three runs -- one earned -- on seven hits and four walks over 5 2/3 innings en route to his second loss. Cosart is ranked No. 60 by MLB.com and No. 2 in the Astros' system behind first baseman Jonathan Singleton, who went 0-for-4 in the loss.