Back in the day when pro football was a contact sport, it was not unusual to see player's face masks clogged with chunks of grass and mud collected from a face plant in the dirt. Times changed and more and more NFL stadiums went to artificial turf and eventually the Field Turf that you see at so many NFL stadiums today.

While that field turf is often touted as being very close to playing on a natural grass surface it certainly doesn't seem to get that kind of a glowing endorsement from the men who have to play the games on it. Many NFL players believe that field turf is the reason that so many of the game's players have been injured or at least had their playing days shortened.

Monday the NFL Players Association reached out to NFL owners formally calling on league owners to return the playing surfaces at their stadiums to natural grass. The letter to the owners cited claims of higher injury rates to players who are asked to perform on fields that use artificial turf.

In the open letter penned by NFLPA President J.C. Tretter, who is in his eighth season as the center for the Cleveland Browns, Tetter claimed that  "The unforgiving nature of artificial turf compounds the grind on the body we already bear from playing a contact sport"

Currently, 17 of the NFL's 31 stadiums use traditional grass. Surprisingly two indoor stadiums, the ones in Las Vegas and Phoenix, use natural grass. Meanwhile, other indoor stadiums such as the Mercedes-Benz Superdome use field turf.

In Tetter's letter to the NFL owners, he cited a statistic that the injury rate for lower body non-contact injuries to players is 28% higher on artificial turf than it is on a grass surface.

So far there has been no response from NFL owners but when you consider NFL stars such as Odell Beckham Jr, Nick Bosa, and Jimmy Garoppolo have had to or are currently dealing with injuries suffered on artificial turf you can bet the issue will be looked into further.