OFFICIAL: @Braves sign four-time All-Star RHP Ben Sheets to Minor League contract.— MLB (@MLB) July 1, 2012
Not only was he signed, but apparently he's in uniform throwing a bullpen session at Turner Field on Sunday. That suggests that he was going to skip the whole minor-league tune-up part, but according to Danny Knobler, Sheets will start for the Braves' AA affiliate on July 4.
Sheets is still just 33, which is probably about five years younger than you were thinking. He threw 20 games in 2010 for the Oakland A's, compiling a 4.53 ERA before having season-sending elbow surgery. He missed the 2009 season because of elbow surgery as well, but he made the All-Star team in both 2007 and 2008.
In 2004, Sheets had one of the greatest single-season strikeout-to-walk ratios ever, striking out 264 and walking 32 in 237 innings.