Kevin Bowen of the team's official website reports that Richardson did not make the trip to New England due to personal reasons.
Richardson told ESPN.com on Sunday that he missed the Colts' walk through because he's dealing with "a very serious family emergency."
"I'm still at the hospital," he added. "I wouldn't purposely just miss walk through."
Richardson's play never improved this season and his role was drastically diminished. He took one snap in the Wild Card round and was inactive last week. There was some speculation that Richardson's poor play and diminished duties were due to weight issues. The running back brushed off those theories this week.
Whatever the reason for him missing Sunday's matchup, this is just the latest in a long line of setbacks for the running back who has adamantly insisted he'd turn things around in Indy.
Herron has proven to be a much better fit in the Colts' offense. In two playoff games he has 35 carries, 119 yards (3.4 yards per carry) and two touchdowns. He also added 18 receptions for 117 yards. Herron is a tough runner with some big burst ability. His elevation in the passing game -- both blocking and catching -- has made life much easier on Andrew Luck the past several weeks.