If you're drafted outside the first round in baseball you get a signing bonus under $2M and then you've got potentially years in the minors making under $20k/year. And then once you make the majors you get the league min ($600k) for 3 years until you hit arbitration.
Whereas a guy drafted in the middle of the 4th round of th NFL draft gets a 4 yr/$4M deal with another $750k in the signing bonus.
So unless you make the majors really quick and have a much longer career, NFL money is better. And definitely has a much higher floor