If he comes back and makes the All American team next season then he could easily be a late day 1 or early day 2 pick. It's a pretty substantial difference.
Say he went to the draft this year and was drafted in the 6th round. His contract would be somewhere around 2.7 million over 4 years which would roughly be $675,000/a year. There is little to no guarantees getting picked that late.
If he came back and was an early 2nd round pick next year then he's looking at around 7 million over 4 years. So you're talking about a 4-5 million dollar difference over 4 years.
Just for fun say he comes back and is a 1st team All American and is drafted in the 1st round then he would be looking at 16-18 million over 4 years.
I truly believe if he comes back next season and we see a similar jump like we did from his this year then he's without a doubt at worst a late 2nd round pick.