From NFL.com: "I could play on Sunday," Ryan Grant said. "Unfortunately." Unlike some players, such as Maurkice Pouncey, who really wanted to play but in the end just wasn't healthy, Grant might really be healthy. Grant's injury happened so early in the season that it was possible that he could return.
The Green Bay Packers didn't feel like they could lose that roster spot all season. They didn't feel they could wait for a player who might not be in game shape when he was finally ready to return at the end of the season. It was a reasonable decision at the time, but that was in the context of a 16 game schedule. Not the expanded 20 game playoff run.
Instead we've spent a couple weeks trying to determine if RB James Starks can run against the Steelers. Instead we could have been talking about how the Steelers will try and contain Grant. All so the Packers can have RB Dimitri Nance instead of Grant on the roster. It looks like a poor decision in hindsight, but it was a tough call back in week 1.