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A minor-league pitcher accused of throwing a baseball during a brawl that struck and injured a fan in the stands had been angry and decided to hurt someone, a prosecutor said Tuesday.

In opening statements during the trial of Julio Castillo, assistant Montgomery County prosecutor Jon Marshall said the evidence will show that Castillo, 22, of the Dominican Republic, committed felonious assault.

"He decided he was going to hurt someone, anyone," Marshall said. "He had in his hand a hard dense object, a baseball. He decided to hurl that baseball, that object, with great force."

Castillo, who was pitching for the Peoria Chiefs, is accused of throwing a baseball into the stands during a 10-minute, bench-clearing brawl last July when the Chiefs played the Dayton Dragons.

Marshall said Chris McCarthy was sitting in the stands with his wife and young son when the ball hurled by Castillo hit him.

"The ball struck him square in the temple," Marshall said. "He didn't have time to react."

Marshall said McCarthy was taken to a hospital, where he was diagnosed with a concussion.

"The stitching of the ball the defendant threw was imprinted on Chris' head," he said.

Defense attorney Dennis Lieberman said that as tensions between the two teams escalated, Castillo threw the ball at the Dayton dugout to keep Dragons' players from rushing the field.

"He throws it at the dugout — at the fencing in front of the dugout — to hit an inanimate object to scare them away," Lieberman said. "He does it because he can't talk. He can't speak English. ... He wasn't throwing it at an individual."

Castillo has been charged with two counts of felonious assault — felonious assault with a deadly weapon and felonious assault causing serious physical harm. He has pleaded not guilty. If convicted on both charges and sentenced to consecutive terms, he could face up to 16 years in prison.

Castillo is on the roster of the Boise Hawks, a Class A affiliate of the Chicago Cubs, but is not allowed to play. The Cubs are awaiting the outcome of the trial to determine whether that status will change.

Prosecutors say Castillo was attempting to hit a Dayton player in the dugout, but instead struck the fan in the head. Montgomery County Prosecutor Mathias Heck Jr. has said Castillo threw the baseball to purposely hurt someone, putting spectators that included children in danger. Defense attorney Dennis Lieberman has said the charges aren't justified by the circumstances.

"He obviously threw the ball," Lieberman said Monday. "But for it to be a crime of this nature he would have to know he was going to cause serious physical harm. We don't believe that's the case."

In the previous game before the brawl, three Peoria batters had been hit by pitches. In the next game, a Peoria player was hit in the top of the first inning, then Castillo hit two Dayton batters in the bottom half — one in the head. The second batter hit by Castillo, Angel Cabrerra, made an aggressive slide into second to break up a double play.

Castillo followed that by throwing his next pitch up-and-in, prompting Dayton manager Donnie Scott to complain to the home plate umpire. Interim Peoria manager Carmelo Martinez came onto the field to join the discussion. The two managers began arguing, and when Martinez pushed Scott, the benches emptied.

Video from the game shows Castillo throwing a ball, but doesn't show where the ball landed.

Officials in the Midwest League suspended and fined 15 players and both managers for the fight.