He will undergo surgery Monday in Denver and should be ready for spring training next season.
"He's bummed," manager Bud Black said. "I think every player wants to finish the season on the field and healthy. Charlie sets such a great standard for durability and finishing out a season. He's bummed because he wants to play."
The injury occurred last week, but Blackmon tried to play through it as long as he could.
"I think it sort of got to the point where he was probably not going to be able to function like Charlie needs to function, or any athlete," Black said. "Charlie's a competitor. He likes to be on the field. He likes to play. So this is a bummer."