Yes, you should use small cleats on artificial turf instead of long grass spikes, doing so results in much lower torque on leg tendons. The problem is, like players not feeling comfortable in the Revolution helmets or wearing leg pads, using short spikes results in inferior grip and cutting ability, so they play slower. If you're wearing small cleats and the guy across from you is wearing grass cleats, you're going to be at a competitive disadvantage until they cart your opponent off the field. I would suspect the NFL has equipment rules to maintain safety (high school football usually does, including cleat length) but I can't recall a penalty or fine given for an equipment infraction (aside from Clinton Portis' socks etc.)
That's some of it. Also, that the field IS maintainable under anything approaching normal use late into the season. Many teams with natural grass resort to resodding their field every game late in the season, the result being that they turn into soup during wet weather or simply detach from the loam.
Most prevalent on the old hard AstroTurf, but it happens on grass all the time, as its an injury that usually occurs when a player is being piled on when going down (skill position), or has weight put on his calf when on a knee (linemen). It's an issue of athletic shoes not having stiff enough soles. According to the NFLPA, players choose shoes based on comfort and lightness; toe flexion protection is not the leading criteria.
Player performance, plus it was felt that the low quality turf was causing leg injuries. It was a season after the poor natural grass at Heinz Field was implicated in injuries to Rodney Harrison and Matt Light during the same game.
The Ravens have played on artificial turf since 2003, after their natural surface crapped out. They were actually one of the first outdoor fields to make the switch, after Seattle.
Lambeau Field is used for literally NOTHING else apart from Packers football. They used to resod it every week late in the season and then heat and tarp it, giving it that distinctive brown color on game day. After it was ranked one of the worst playing surfaces in the NFL for a couple of NFLPA surveys the Packers went to a hybrid field in 2006, so it is no longer natural grass. But they still can't even play high school games on it.
The full results from those surveys:
source:
Artificial-Or-Natural-Players-Respond / News - NFLPlayers.com
Foxboro is an inclement weather city, and the 2008 survey notes that New England changed to FieldTurf, while Pittsburgh simply resodded, and again came in as
one of the worst fields in the NFL. Infilled turf is popular because there isn't a good way to get a consistent natural grass surface throughout the season anywhere north of Washington. Denver alone doesn't seem to have big problems, probably because they get a lot of sunlight year round.
Personally I played on this stuff for years in high school and college and never witnessed an attributable injury to "caught" cleats. This was after hyperextending both my knees in middle school and high school playing on natural grass fields due to the grass tearing out from under me while my legs were under stress. Probably if I was older and no so elastic those would have been severe ligament tears.
However, I've never played at a level where the force exerted by players was up to NFL standards, so there is no doubt a special concern for skill players at that level. But it can be managed much better via equipment than the alternative.
Also, my understanding is that MRSA is usually a problem only on indoor fields, which must be frequently disinfected. Natural sunlight and weather works as a natural disinfectant on outdoor surfaces.
