A week after the Green Bay Packers were forced to keep Cedric Benson on injured reserve, another injury blow to the position is likely to force GM Ted Thompson into acquisition mode at running back.

NOTE: Jason Wilde is reporting Wednesday morning that the Packers have agreed to terms with former running back Ryan Grant. 

Jason Wilde of ESPN Milwaukee reported Tuesday night that running back James Starks, who has been platooning in the Packers backfield with Alex Green, suffered a knee injury against the Minnesota Vikings Sunday and is now in danger of landing on season-ending injured reserve.

According to an NFL source, Starks was later diagnosed with a knee injury, suffered during Sunday’s 23-14 victory over the Minnesota Vikings, and it’s serious enough that he might not play again the rest of the season. The source said the Packers are mulling placing Starks on injured reserve.

Starks carried 15 times for 66 yards and a 22-yard touchdown in the Packers' 23-14 win over the Vikings. He is second on the team this season with 255 yards rushing.

His injury occurred in the fourth quarter Sunday when Vikings cornerback Josh Robinson upended Starks on an outside run. While limping off and appearing in pain on the sideline afterwards, Starks did return to carry three more times.

If Starks is forced to go on IR, he'll become the third Packers running back to do so this season. Benson (Lisfranc injury) and Brandon Saine (ACL) already occupy a spot on the list, and if Starks joins them, it would leave Green, Johnny White and DuJuan Harris as the only true running backs left on the Packers active roster.

White, signed in October, missed Week 13 with a concussion suffered against the New York Giants, while Harris was signed last Saturday from the practice squad. Green, a 2011 third-round pick, leads the team with 360 rushing yards.

Fullback John Kuhn has also shared ball-carrying duties, both this season (eight carries last two games) and in the past. In 2010, Kuhn tallied a career-high 84 carries after the Packers were ravaged by injury at the running back position.

If Thompson does place Starks on IR and wants to add a veteran free agent off the street, he'll have some options. However, it's equally possible that Thompson avoids a big-name, experienced back and plucks a young player off someone's practice squad.

Below is a list of the top available free agents at running back, via Adam Caplan of the The Sideline View. I added my own context for some of the bigger names.

Joseph Addai
5-11, 214 lbs. 

Addai signed with the New England Patriots in May but was released after he failed his team physical before training camp. His only reported workout since came with the New York Giants a few weeks back, but nothing came from the look. At 29 years old, Addai only has value as a pass-protecting, third-down option.

Ryan Grant
6-1, 222  

The Packers have had ample opportunity to bring Grant back, but not even a whisper of interest has come about. It's safe now to wonder if Thompson and head coach Mike McCarthy are done with the 29-year-old back. Cut by the Redskins in October, Grant's last chance at a reunion could come from Starks' injury. He knows the system, staff and locker room.

Tim Hightower
6-0, 222 

10 months after tearing his ACL, Hightower was cut by the Redskins after he had a setback during the preseason. In September, Washington passed on re-signing Hightower because it was discovered he needed a scope in the same knee. He should be close to healthy now, however. Hightower has 24 career touchdowns and 128 catches in four NFL seasons.

Steve Slaton
5-9, 200 

Slaton, 26, has received interest from a few clubs this season, including the Broncos, Jets, Bears and Lions. But Slaton is still without a team, mostly because he hasn't contributed to an offense since 2009. However, former Packers offensive coordinator Joe Philbin was intrigued this offseason with his potential ability in the zone-blocking run system. He rushed for 120 yards against the Packers in 2008 as a member of the Houston Texans.

Carnell "Cadillac" Williams
5-11, 218

The 30-year-old back hasn't received a sniff of interest since the Rams let him walk in free agency last spring. With a career rushing average under 4.0, Williams may not play another snap in the NFL. Why he is this high on Caplan's list, I don't know.

Mewelde Moore
5-11, 209

The former Vikings and Steelers third-down back was released by the Colts in October. In six games, Moore rushed six times for nine yards and caught four passes for 36 yards and a touchdown. Indianapolis isn't exactly overflowing with talented running backs, so Moore's release might reveal a deeper flaw that is scaring teams away.

Thomas Jones
5-10, 212

At 34 years old, Jones hasn't played since 2011. His name being so high up Caplan's list is somewhat puzzling. It's hard to see the hard-nosed and hard-headed back getting another NFL shot.

Maurice Morris
5-11, 216

Morris was last seen with the Lions in 2011, when he recorded nearly 550 yards of total offense for a Detroit roster that was also dealing with a number of injuries at running back. He caught nine passes for 81 yards against the Packers last November in Detroit.

Dimitri Nance
5-10, 219

Nance played in 12 games for the Packers in 2010, rushing 36 times for 95 yards and catching three passes for 30. He hasn't seen a snap since, despite the Falcons taking a futures flier on him last January. Nance is a plodding runner who does have the body to pass protect.

Tyrell Sutton
5-8 213

As recently as two years ago, Sutton appeared to have a lot of admirers around the league. That perceived interest dried up in a hurry after he was cut from the Panthers before the 2011 season. After spending a year out of the league, Sutton re-emerged this past offseason in Seattle, but the Seahawks also cut him. Sutton got his NFL start with the Packers as an undrafted free agent out of Northwestern in 2009. Carolina claimed him that same season after Green Bay tried to get him back on the practice squad. The Packers did give Sutton a work out last December.

Graig Cooper
5-10, 205

The Eagles kicked the tires twice on Cooper, a former University of Miami standout who likely would have been drafted in 2011 had he not blown out his knee. The Packers also worked him out last December, along with Sutton, Jalen Parmele (currently in Jacksonville) and Walter Sanders. Cooper has third-down and special teams potential.

Other names included:  

Deji Karim
Lorenzo Booker
Harvey Unga
Chester Taylor
Rock Cartwright
Kareem Huggins
Xavier Omon
James Davis
Thomas Clayton
Curtis Brinkley
Keith Toston
Chris Taylor
Josh Vaughan
Lonyae Miller
Mossis Madu
John Clay

Zach Kruse is a 24-year-old sports writer who contributes to Cheesehead TV, Bleacher Report and the Milwaukee Journal Sentinel. He also covers prep sports for the Dunn Co. News. You can reach him on Twitter @zachkruse2 or by email at [email protected].