It depends on what you mean by front-loading. Yes, the bonus is paid at the front, but it's spreadh evenly across the years of the contract in terms of cap hit. This is exactly how it works in the NFL.

Actually it is not spread evenly, the team and player can structure the cap hits into the different seasons however they see fit.

For example http://www.spotrac.com/nfl/miami-dolphins/ndamukong-suh/

Holy ****. When did that change? I've been paying attention to salary caps and cap rules for over two decades and I had no idea that was the case. In fact, I know for a fact it wasn't for a long time. I wonder if the latest CBA was where that changed.

Regardless, thanks for dropping some knowledge on me.

that's not a front loaded bonus, that is how bonus's work in the nfl the actual rule is that the cap is evenly spread for the life of the contract. with a maximum spread of 5 years it's just that MFN spreads it over the entire 6 which helps with cap space instead of restricting the bonus cap hit to the first 5 years of the contract, you will notice in the example the bonus hit is 5,100,000 each of the first 5 years

You're right. I was looking at the total cap hit, not the signing bonus. OK...sanity restored.