First of all, how many predicted Leon Patton to be the starting running back as a true freshman last season?
Secondly, I believe if you have the right scheme and good enough blocking up front, the running back position is the easiest position to replace in all of football.
Now, looking back at Rivals rankings for '06... Leon Patton was a 3-star, 5.5 rating, #61 overall athlete coming out of the state of Texas.
In comparison, Donte Bean, the guy I would like to see fill Cornish's spot, was a 3-star, 5.6 rating, #15 overall all-purpose back and ranked in the Texas Top 100 coming out of high school. Bean has better measurements than Patton, as well as a 4.43 40-time and a 4.25 shuttle time. I expect him to get a lot of carries next season.
Another option at running back is Angus Quigley, who was projected as the 2nd-string running back behind Cornish last season until he had a season-ending injury. Quigley stands 6'3, 210, with 4.5 speed. Rivals gave him a 3-star, 5.6 ranking, and he's another guy from the state of Texas, which produces tons of talented football players.
Next on the list is Jake Sharp, who I'm sure you all know about. Sharp was the #1 ranked player in Kansas and the #17 overall all-purpose back in '06. He was an EA Sports All-American and broke all sorts of rushing records for the state of Kansas. Rivals gave him a 3-star, 5.6 rating. He averaged a little over 6 yards per carry last season as a true freshman. Sharp also took 2nd in the state in the 100-meter sprint. K-State tried to make a late push, but he stuck with ku.
Now, after I've listed three players who were ranked higher coming out of high school than Leon Patton (your starting RB), with better size and speed, is there some other reason why you think ku doesn't have anyone to replace Cornish?