San Diego State's Erik Castro always knew it was essential to have a catcher. Otherwise, the ball would go all the way to the backstop when the pitcher threw it.

Castro knew little about catching beyond that, and he didn't care to know more.

Castro, a 6-foot-3, 210-pound sophomore, was an all-state third baseman at Fallbrook High. He played first and third last season at the University of Arizona and had similar plans after transferring to SDSU.

That all changed when Aztecs starting catcher Matt Parker was lost for the year shortly before the season opener with a stress fracture in his right ankle.

The Aztecs tried five players behind the plate in the season's early going. It wasn't pretty. Balls ricocheted off the glove, going here, there and everywhere. Teams like BYU, which stole seven bases in one game, were running at will. Castro stepped up, and he has made steady improvement.

“I just love the fact he was willing to put the stuff on and go back there and get beat up,” said SDSU coach Tony Gwynn. “Having never caught before to be where he is now is pretty amazing.

“It's been amazing to watch the transformation. He's blocking balls better. He's throwing guys out. He's taking charge back there. . . . The biggest thing is he's giving a target and he 3/8s receiving, he isn't catching.”

Castro welcomed the opportunity to go behind the plate, saying, “If I get to play, it sounds good to me.” His learning curve was aided working with SDSU pitching coach Rusty Filter, a pitcher and catcher at Mission Bay High and SDSU in the 1980s.

“He taught me really how to catch the ball,” said Castro. “I really had to be taught how to go get the ball. . . . I feel real comfortable now. It feels real natural. I can just give signs, block the ball, throw the ball. I'm in sync with the pitchers, good chemistry.”

Catching may have hindered his hitting – he's batting .224 with three homers and 20 RBI – although Castro won't make excuses.

“I've just been going through a hard time hitting,” he said. “I just need to start hitting the ball hard.” Castro's brief time behind the plate already includes what certainly will be a lifetime memory. He was catching teammate Stephen Strasburg two weeks ago when the right-hander struck out a school-record 23 batters against Utah.

“That was amazing,” said Castro. “He hit every spot. It was real easy. I barely had to move the glove. . . . I was sitting there with the umpire and we were just, 'Oh, my gosh. These guys have no shot.' He didn't miss.

“Catching that last strike. It was a real good.”