Baltimore Ravens cornerback Jimmy Smith, who suffered a season-ending Achilles injury Sunday, has been suspended four games for violating the NFL's policy on performance-enhancing substances, a source told ESPN's Adam Schefter.

Smith, the Ravens' top cornerback, decided to drop his appeal and begin serving his suspension after suffering a torn Achilles injury in Sunday's 44-20 victory over the Detroit Lions, the source told Schefter.

The Ravens are expected to place Smith on injured reserve this week. This puts a smudge on what had been Smith's finest season in the NFL. He made three interceptions and led the Ravens with nine passes broken up.