No, there is no added risk because of the opt out. If you sign a guy for 10 years for $300 million with no opt out and he gets injured and stinks, even in the first 2-3 years, the team loses. That is the nature of a guaranteed long-term deal. The player has to give up something to get the opt out. So, lets say to have a 3-year opt out, the contract is only $290 million. In the above case, the team's loss is a little less. Now, let's say you front-load the contract and include an opt out clause after the 3rd season. You are inviting, strongly incentivizing the guy to opt out after the 3rd year because, since the annual salary drops, he is likelier to get a better FA deal if he opts out. He has this in mind from the day he signs the contract, so he is playing for a relatively soon next contract. This doesn't protect you from injury. It does protect you from sloth, to a certain extent. But, more importantly it does 2 things: 1) you don't own his contract when the inevitable age-related decline occurs in the back end of the deal and 2)you aren't paying out big $ to him at a time when your salary budget is crimped and you need to resign your own players or sign another FA. The downside for most teams is that you are over-paying for the first 3 years and that hurts your budget. You may be overpaying for the 10 years as a whole, which hurts your AAV and puts you over the lux cap. Here is where the Phillies have the advantage. They are WAAAY under the lux cap for those first 3 years. They are WAY under the salary budget which their revenue can support. AND, also unique to the Phillies, they have Trout sitting out there who would love to be a Phillie in two years and is a better fit than Harper. So, the 3 year out pinches you in year 3, perhaps we exceed the lux cap for one season, but in that season, with both Harper and Trout, we have the sort of enhanced chance to go to (and win?) a WS that we would have had if the Phillies ownership had been willing to go over budget for 1 year to have both Lee and Halladay. Monty wouldn't do that -- the budget was the budget. Middleton will do it. Next year, back under the lux cap, no harm done.
All things considered, the opt out decreases the risk to the team. Where it could hurt is if the guy turns out to be great for all 10 years of the deal and we only get the benefit of the first 3. In this case, Trout fixes that.