Concussion has become a polarizing medical ailment across the sports community in recent years. The four major sports have implemented a protocol when dealing with head injuries as alarming health consequences have been revealed and seen in retired athletes.

Just hours before they were to take on the New York Knicks in Game 5 of their semifinal playoff series on Thursday night, the Indiana Pacers learned that they would be without George Hill because of a concussion suffered two nights earlier. Hill, who took a number of hard blows in Game 4, reportedly suffered the head injury on a hard foul by Tyson Chandler.

Hill complained of a headache during the Pacers' morning practice session on Thursday and took the NBA’s required concussion test a few hours later. He failed and was forced to watch his team lose at Madison Square Garden from the dimly-lit trainer’s room.

Hindsight is 20/20 and a concussion is a serious issue, but you have to wonder when Hill began feeling the symptoms. Frank Vogel said Thursday night that the point guard felt symptoms “at some point over the last two days.”

As Mike Wells astutely reported, Tyler Hansbrough urged Hill to undergo testing for a concussion. Hansbrough dealt with vertigo during his rookie season after suffering one.

The NBA instituted uniform concussion protocol before the 2011-12 season, making this season the first full campaign of its existence. There are undoubtedly numerous concussions that go undiagnosed. A player must feel the right symptoms, disclose them to his team’s medical staff and then they must be deemed serious enough for testing. From player to player, pain levels vary and the male ego comes into play as well.

It’s possible that in this case Hill felt off on Wednesday, but decided to wait before informing any team employees. Indiana went into Game 5 with a 3-1 series lead and three chances to eliminate New York and advance to the Eastern Conference Finals.

By my count, there were 13 diagnosed concussions in the NBA this season (including Hill and not including Harrison Barnes) that officially made their way onto a medical report. Darrell Arthur of the Memphis Grizzlies suffered two in less than three months, which makes him an interesting case going forward.

As you might expect, the wording of the league policy leaves a lot to infer. The Pacers have listed Hill as “day-to-day,” which makes sense given that the season is day-to-day in the playoffs. A player must pass a series of tests before returning to the floor, including a handful of non-contact and conditioning drills. There is a line in the rulebook that has alarmed many around the Pacers: “The process will likely take at least several days, if not weeks.”

Every case is different and all that means is that it’s impossible to determine when he will return. However, there is precedent for Hill to return as early as Saturday night, if not for possible games on Monday (Game 7) or Wednesday (Game 1 against the Miami Heat).

Arthur absorbed a blow to the head on Dec. 14, 2012 and initially had a “dental issue.” He was then diagnosed with what the Grizzlies called a “mild” concussion and missed the team’s next game. He was back on the floor three days later on Dec. 17, 2012. Arthur suffered a second concussion on March 3 and didn’t suit up again until March 22. There has been no indication that his quick return from the first concussion led to the second.

When looking at cases this season, I wasn’t concerned with the number of games missed by a concussed player, but rather the number of days they sat out. My sample size dropped to 11 cases because C.J. Miles of the Cleveland Cavaliers suffered a concussion on April 7 and never played another game.

Those players that failed a concussion test and returned this season – John Jenkins, Nikola Vucevic, Darrell Arthur, Michael Kidd-Gilchrist, Chris Kaman, Pau Gasol, Marvin Williams, Jeff Pendergraph and Anthony Davis – missed an average of 11 days.

Chris Kaman missed 27 days spanning January and February with a severe concussion, while Jenkins, Kidd-Gilchrist, Williams, Pendergraph and Davis all missed about a week.

It’s impossible to predict when Hill will be able to return to the floor – it could be Saturday, a few games into a potential series with the Heat or even the first game of the 2013-14 season – and to try and guess one way or the other is a losing proposition.