The UFC announced on Friday that Riddle was out of the bout, and taking his place will be Pennsylvania native Charlie Brenneman.
The 30-year-old Brenneman brings a 12-2 career record to this fight, including a 2-1 mark inside the Octagon. After making a successful UFC debut with a decision win over Jason High last March, Brenneman suffered the first stoppage loss of his career to Johny Hendricks at UFC 117. But he came back strong, earning a decision win over Amilcar Alves at UFC Fight for the Troops 2 in January.
Grant has gone 3-3 in six fights in the UFC, swapping wins and losses along the way. In his most recent fight, he dropped a decision to Ricardo Almeida, which will go down as Almeida's final win as he retired from the sport following his loss at UFC 128.
UFC on Versus 4 takes place from the Consol Energy Center in Pittsburgh, Penn., headlined by a welterweight bout between Nate Marquardt and Anthony "Rumble" Johnson.
Penick's Analysis: Riddle's been hit by a lot of injuries over the last few years, which is really unfortunate for him because he's still only 25 years old. The multitude of injuries could lead to his career being significantly shortened, but hopefully he can work through this latest one and heal up before returning to action. Brenneman is a good replacement for him in this fight, though, and it's a great opportunity for him to fight in his home state. Grant will want to get back in the win column, but it will be another tough fight for him here. It's a good fight for the preliminary card, though.