CHICAGO (WSCR) Chicago Cubs shortstop Starlin Castro had an amazing start to his 2011 season. Through the first month of the season he had a .348 batting average with 18 runs scored, 12 runs batted in and two triples.

But when the calender switched over to May, the 21-year old’s production hit a snag. Through nine game in the month of May, Castro is hitting just .242 with four RBI and three runs scored, sparking some to wonder what caused such a drastic change.

“I think the change we’ve seen is the way teams are attacking him,” Bob Brenly said on Wednesday’s Danny Mac Show. “Earlier in the season, they were trying to get ahead, throwing a lot of strikes. Starlin has such great hand-eye coordination, he feels like he can hit everything. When opposing pitchers throw the ball in or near the strike zone, he is going to hit it.

LISTEN: Bob Brenly On The Danny Mac Show Show

“But what we’ve seen now, is they’ve really started just expanding the strike zone from the very first pitch, they don’t even try to throw a strike to get ahead in the count and then expand the zone. They’re throwing curve balls in the dirt, they’re throwing fastballs up above the letters first pitch. They throwing fastballs off the outside corner first pitch. And because of his aggressive nature and his confidence that he can put the bat on any pitch that’s thrown up there, he’s gotten himself out a lot lately, he’s put a lot of balls into play weakly.

“I don’t think his approach has changed whatsoever. Now he needs to make the adjustment and force teams back into the strike zone.”

In Wednesday night’s 11-4 win over the St. Louis Cardinals, Castro was 4-for-4 with three runs scored and three RBI.