NEW : A variety of Twitter reaction to charges . Comment: Peterson was the NFL MVP in 2012 ; his 2-year-old son died last year .
NEW : A variety of Twitter reaction to charges . Peterson 's attorney says the charge stemmed from `` using a switch to spank his son '' `` Adrian ... deeply regrets the unintentional injury , '' the lawyer Rusty Hardin adds . Peterson was the NFL MVP in 2012 ; his 2-year-old son died last year .