APOPKA, Fla. -

With Apopka High School quarterback Zack Darlington being knocked unconscious on ESPN in the team's season opener, the play has parents concerned about concussions.

Darlington, 18, was rushing to the sideline when he was hit near the end of the game on Saturday in South Carolina. As he fell, Darlington's head hit the ground, knocking him unconscious and he was airlifted to a hospital.

[VIDEO: Health experts sound off]

Darlington, who has a full-ride athletic scholarship to University of Nebraska, was released from the hospital on Sunday.

"This particular one was an accident, it was a legal play it was unfortunate," said Matthew Fitzpatrick, Orange County Public Schools District Athletic Director.

Dr. Todd Maugans, chief of Neurosurgery at Nemours Children's Hospital says a hit like Darlington's could be career-ending.

"For many athletes, there can be a point of no return when that next hit can be the one that will give them a lifelong problem with headaches, depression, declining mental function," he said.

Maugans has been pushing for stricter rules when it comes to athletes getting back on the field after a concussion.

"The rules were that you could grade a concussion and if a person had transient symptoms only lasting a few minutes, then perhaps they could play that day," Maugans said. "We now have ample evidence that that is just frankly dangerous."

Fitzpatrick said he couldn't speak about Darlington but said he won't be back on the field until he's cleared.

"They have to be cleared by a medical doctor that has specialized in concussion injuries, this is not something that is done at the school level," said Fitzpatrick. "This is something that's done by a medical doctor that clears them to guarantee and insure the safety of all players."

A year ago, doctors had a more arbitrary way, the severity dictated how soon the player could come back. But a tougher bill enacted in 2012 is supposed to tackle that problem.

"I think we're diagnosing them better and I think we have steps in place that treat them better," said Fitzpatrick.

The new program measures the students' progress every day so the earliest they could play again would be 4 days later.

The Blue Darters' next game is Friday. It's not clear when Darlington will be cleared to play.

Darlington's father issued a statement on Monday stating:

First of all, we would like to thank everyone for the thousands of texts, emails, and phone calls of support over the last few days. It has certainly been a tough time for Zack and our family.

In the last two months, Zack has suffered two concussions. Since the first incident he has been under the care of two excellent doctors, James Michael Ray at the National Training Center in Clermont and Sam Slobounov of Penn State University, one the nation’s foremost experts on concussions. He has undergone countless tests, MRI’s, CTI’s, cat scans, etc. to make sure he was ready to play safely.

As has been documented, with each concussion, the brain is more susceptible to future concussions. For Zack to fully recover from this latest injury will take time. We do not have a timetable for his return, but we fully trust in the medical care and opinions of Dr. Ray and Dr. Slobonouv. Zack saw them today, underwent several tests, and performed surprisingly well. He has suffered no permanent damage and his physicians expect a full recovery. It will take time for Zack to heal completely and not be susceptible to further concussions, and we will make sure that he has that time to recover and pursue his dreams.

I spoke with Bo Pelini, the head football coach at the University of Nebraska this morning. He told me that if Zack plays again this year, if he doesn’t play this year, or if he never plays football again, they want him as a Cornhusker. This type of integrity and loyalty is why Zack chose Nebraska as his college destination, and we are very thankful to Coach Pelini and his staff for their support of my son not just as a football player, but as a young man.

This is a difficult time for Zack and our family. Many tears have been shed and many prayers said, not only for healing, but for wisdom and comfort. Zack has been our emotional and spiritual leader, both on and off the field. Now God has a new role for him, and although it is hard to not be out there running the Blue Darter offense, he has embraced his new role as a motivator, mentor, and coach as he heals and gets ready for the future.

As a father, I am so proud of him for the love he has for his teammates, the toughness and resilence he has shown in battling adversity, and his steadfast belief that God’s plan for him is an amazing one, even though it is normal to question that in a tough time like this. Zack’s health and future are our top priority, and although we’d all love to have him leading us on the field, it is far more important that he moves on to college and with God’s grace in time becomes the leader of his own family and whatever group God uses him to lead.

Thank you for your concern and understanding. Our family is truly thankful that Zack is going to be fine, and for the support and encouragement of so many. Although we are sad now, we know that God has a great plan for Zack and we look forward to watching it unfold.

Click here to learn more about Orange County Public School's concussions protocol.