Broken collarbone.
via NFL.COM Player News:
Colston (broken collarbone) will miss at least four weeks, Fox Sports' Jay Glazer reports.
Impacts: Colston's absence raises the value of Robert Meachem and Devery Henderson for the next month or so, and the same is true for Lance Moore (groin) whenever he returns. If there's a silver lining here, it might be that the time off should result in less strain on his knee, hopefully allowing him to be in better shape around midseason than he otherwise would be.