A spokesman at Hahnemann University Hospital said Dixon was in critical condition Wednesday morning.
No arrests have been made in the latest shooting.
Dixon was convicted in January of lying to police about the earlier shooting, which happened April 28, 2008. His lawyers say he initially lied to police because he feared Harrison.
Investigators determined that a gun owned by Harrison was used in that shooting. Authorities said no charges were filed because of conflicting accounts of who pulled the trigger.
The Colts released Harrison in February.
