81204
In March 2010 , the NFL announced that this repositioning would be permanent , after five major injuries were suffered by umpires in 2009 ( two concussions and three knee or shoulder injuries requiring surgery ) .
 NFL
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 NFL