Former NFL great Herschel Walker isn't the only Strikeforce heavyweight now on the shelf. 

Valentijn Overeem, older brother of Strikeforce Heavyweight Champion Alistair Overeem, has suffered an undisclosed injury and will no longer be fighting Antonio Silva at Strikeforce: "Henderson vs Babalu" on Dec. 4 in St. Louis, Missouri, according to MMA Weekly.

The "Python" was all set to make his debut with the San Jose based promotion on the strength of a two-fight winning steak and was supposed to add some depth to the heavyweight division.

Strikeforce will have just one week to see if they can find a replacement for "Bigfoot" Silva.

Having won seven of his past eight fights, including a decision win over Andrei Arlovski back in May of this year (2010), Silva was looking to build momentum in the hopes of securing a fight with Valentijn's older brother. At one point he was also rumored to fight Fedor Emelianenko but that never materialized.

With all the turmoil amongst the 265-pound weight class, perhaps it's something Strikeforce will have to revisit.

Strikeforce: "Henderson vs Babalu" is set for Dec. 4 at the Scottrade Center in St. Louis, Missouri and will feature a main event of Dan Henderson vs Renato "Babalu" Sobral.

With injuries to both Walker and Overeem, the main card has lost two of its scheduled main card fights but will still feature Robbie Lawler vs Matt Lindland and Paul Daley vs Scott Smith.

Stay tuned to MMAMania.com for more on this ravaged card as it becomes available.