A second teen football player in New Jersey has died this week from events that occurred during football practice.

Douglas Morales, 17, died Tuesday night of a subdural hematoma, or excessive bleeding in the brain, according to radio station 1010WINS.

The 17-year-old Cliffside Park High School athlete was rushed to the hospital from practice on Friday, Cliffside Park Police Chief Donald Keane told FOXNews.com.

"We received a call at the police station at 11:50 on Friday," Keane said. "The caller said there was an unconscious football player on the field. He (Morales) was unconscious when we got there and we got him into the ambulance right away."

What police do know is that the practice was authorized and coaches were present during the activities, Keane said.

The teen's death came only a day after a Waldwick boy died during football practice on his 13th birthday.

Sean Fisher's mother told The Record of Bergen County she was home making cupcakes for her son's birthday when he lost consciousness Monday.

An EMT rushed onto the field and paramedics used a defibrillator. They were unable to resuscitate him. Fisher was pronounced dead at Valley Hospital in Ridgewood.

Officials are awaiting the results of Sean Fisher's autopsy. The school superintendent says an undetected heart condition is suspected.

Dr. Merle Myerson, a cardiologist and director of St. Luke's Roosevelt Cardiovascular Disease Prevention Program in New York City, said if an athlete suddenly dies, it is generally from a cardiac cause.

"It can be from a fatal irregular heart rhythm, an abnormality of the heart muscle, a problem with the structure of the heart or how the heart is working, or how the electrical condition of the heart is working," Myerson said. "The thing is, it's usually unusual, so when it does happen, it's tragic."

Myerson said more preventative screening is needed for student athletes.

"In Europe, they do it more, the doctors will give the athletes an electrocardiogram, and ask for the family's history, along with a physical exam," she said. "In this country, the whole issue is that sports are being cut, so forget health screenings. They probably just listen to your heart with a stethoscope, but shouldn't we be doing more?"

A funeral Mass will be celebrated Friday for Sean.

The boy was due to enter eighth grade next week.

"These were hometown kids — part of an extended family," Keane said. "The town is in mourning right now."

Click here for more on Sean Fisher.

The Associated Press contributed to this report.