From ATL: Jairus Byrd will "probably" miss some time with his plantar fasciitis. Had it last year, too, but took shots to manage it.— Ian Rapoport (@RapSheet) September 3, 2013
Byrd injured his foot in a Week 2 win over Kansas City last season, and was questionable to play the following week in a road game against Cleveland. After dealing with several other injuries throughout the season, Byrd was listed as probable for the final three weeks of the season on those games' respective injury reports with a foot injury. Rapoport's report implies that the late-season string of games on the injury report were the result of the condition.
Byrd played in all 16 games last season, and played in the Pro Bowl in late January, as well.
Now, the foot issue - combined with the fact that Byrd has still only been back at the team facility for a week and a half following his decision to skip training camp in a contract dispute - looks like it may keep him out of the lineup for the foreseeable future. His expected absence likely explains the team's decision to sign Jim Leonhard to the active roster as a sixth safety; it's a strong bet that we'll see Leonhard on the field in Week 1 against New England.