Curry's head injury brings concussion protocol into question

Stephen Curry's head injury has become the latest chapter in the ongoing debate over when someone should be cleared to get back on the playing field after head trauma.

The decision to allow Curry to re-enter Game 4 in Houston became a point of contention Tuesday, the day after a freakish midair tumble called back into question the effectiveness of standardized concussion testing.

"We know those tests are imperfect," said Chris Nowinski, executive director of the Sports Legacy Institute.

"You can't always tell how bad a concussion will be until 24 hours later," said Cindy Chang, formerly Cal's head team physician and founder of the California Concussion Coalition. "We all saw the injury on TV and saw how shocked and stunned he appeared after the injury."