BRENTWOOD -- East Contra Costa County's sports community remained shocked and saddened after the unexpected death this week of a popular Liberty High assistant freshman baseball coach.

James Anthony Brignolio, a 1990 Liberty graduate, was taken by ambulance to Sutter Delta Medical Center in Antioch on Wednesday after complaining of chest pains during Liberty's baseball practice. He was later pronounced dead at the hospital. He was 42.

The Contra Costa coroner's office Friday still had not determined a cause of death.

He leaves behind a wife and two children, according to the school.

"We want to make sure everyone keeps Tony, his wife and children in their thoughts and prayers," Liberty principal Pat Walsh said.

Liberty baseball players from all three levels, varsity, junior varsity and freshman, were on the field when Brignolio, affectionately known as "Coach Tony," started exhibiting symptoms.

"Our kids had just started working out," Walsh said. "We haven't even selected teams yet, and he was complaining of chest pains at one of the workouts, and so they called 9-1-1."

Walsh said counselors were made available to students Thursday, and a letter was sent home with the baseball players. One school counselor, Chris Jacot, is an assistant baseball coach at Liberty.

Brignolio's passing hit Liberty's senior players hard because he'd connected with them as a friend and a coach, beginning when they were freshmen during his previous stint with the program. He had left Liberty to coach the freshman team at Freedom.

Falcons players had affectionately referred to Brignolio as "Mama Bear."

"A wonderful, wonderful guy," Freedom baseball coach Gary Alexander said. "Big sense of humor, fun-loving. It's just a tragedy."

Former Liberty varsity baseball coach Greg Borland hired Brignolio four or five years ago to coach the Lions freshman team.

"Tony was a really good guy," said Borland, currently a campus supervisor at Freedom. "He came to me when I had the opening, and I hired him right away because of his desire was more of being around the kids than it was the actual baseball. He enjoyed the game, but he loved being around the kids."

Borland said Brignolio was willing to do anything that was needed for the program.

"It didn't matter the time of day, he was there to help me out," Borland said. "He had a really good relationship with the kids. He's really going to be missed."

When Borland stopped coaching at Liberty after a five-year run, he recommended Brignolio to Alexander.

Borland said Brignolio couldn't drive because he suffered from vertigo, but he still found a way to get around.

"It didn't matter how he got there, he was there," Borland said. "That was one of the things amazed me. I'd asked him, 'How'd you get here?' 'Oh, I walked.' It did not matter how he'd get there, he'd just get there."

The family has not yet announced plans for a memorial service or funeral.

Follow Matt Schwab on Twitter at twitter.com/schwab_matt.