Lamar is not the passer that Murray is. A simple look at their stats in their last year of college points that out. Murray last year 4300 yards passing, 43 TDs, 7 INTs, 69% Comp%, 11.6 YPA, 1001 Rushing yards and 12 rushing TDs on 140 attempts. Jackson in 2017 put up 3660 yards passing, 27 TDs, 10 INTs, 59% comp%, 8.5 YPA, 1600 Rushing yards and 18 rushing TDs on 232 attempts. Clearly Jackson was a significantly less effective passer in college and much more reliant on running to be productive and while Murray still did a lot of damage running the ball he was still arguably the best QB in college last year even without the rushing stats.