(ST.JOSEPH, Mo) Chiefs fans were on the edge of their seats after Patrick Mahomes suffered an injury in last week's Playoff game against the Cleveland Browns.

Fred Shonkwiler of Spine and Sport Physical Therapy says, there was no way Mahomes would have been allowed back on the field.

"As soon as he staggered on the field that's considered a gross motor movement abnormality. So, the protocol automatically signified he would be out the rest of the game," said Shonkwiler.

In order for Mahomes to get back on the field this week and to the Super Bowl, he would need to beat Buffalo -- twice.

"It's a 20 - 22 minute test that puts someone on the treadmill, and what we are going to do over the next 20 minutes is measure his tolerance to a graded activity," said Shonkwiler.

Shonkwiler is describing the "Buffalo Concussion Treadmill Test".

The test isn't just as simple as running on a treadmill, athletes like Mahomes are being evaluated every single minute.

"So every minute we were asking him, what's your pain scores, what are your symptom scores," said Shonkwiler.

If the athletes' score increase too much, they are unable to move onto the next phase.

But concussion protocol is not just running on physical exercise.

"So concussion rehab is very involved, much much more than what your exercise tolerance, blood low, aerobic activity. It brings in vision, it brings in balance, it brings in cognitive functioning," said Shonkwiler.

Shonkwiler says with Mahomes practicing, it is a sign that he has passed the critical concussion test, bringing him one step closer to playing on Sunday in the AFC Championship Game.