Castro delivered a two-run single in the fourth and knocked home another run with a base hit two innings later. Rene Tosoni (Twins) led off the game with a homer to center field off Desert Dogs starter Ryohei Tanaka (Orioles).
Shortstop Jose Iglesias, who defected from Cuba over the summer and signed with the Red Sox for $8 million, went 2-for-4 with a double, two RBIs and two runs scored for Mesa.
Bierd (1-0) fanned one and walked one, throwing 19 of 31 pitches for strikes, to pick up the win. Red Sox southpaw Dustin Richardson tossed a pair of scoreless frames and former 12th-round pick Garrett Parcell (Marlins) struck out one in the ninth to close it out.
Tanaka (0-1) was charged with one run on three hits. He struck out four and did not walk a batter.
Rays prospect Heath Rollins struggled in his debut, allowing five runs in the fifth after Nationals right-hander Josh Wilkie surrendered four unearned runs in the fourth.
Chris Marrero (Nationals) homered in the fifth, Brandon Snyder (Orioles) added a two-run shot in the sixth and former Futures Game All-Star Danny Espinosa (Nationals) knocked in three runs for the Desert Dogs.
Danny Wild is an editor for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.