Johnny Gomes and Laynce Nix aren't any better.
I dont think there's any reason for concern in regards to LaRoche and his health. He'll be fine. He's a position player, and a 1st baseman at that. The shoulder injury won't hinder him one bit. If Marrero beats him out in the spring, great. If not, I dont think its a big problem having Marrero get a little more seasoning at AAA next year.
Whether its Marrero or LaRoche, we should get a lot more offense out of that spot. Morse replaces Gomes/Nix/Bernadina/Ankiel in the OF, but basically its Marrero/LaRoche replacing those guys. And whether it's a .260/25 HR LaRoche season or a .280/15 HR season for Marrero, I think it's an improvement.
I also dont think LaRoche is immovable, especially once the spring starts and he shows he's fine. He's a known commodity with one year left on his deal. Even if hes healthy and playing like he normally does, I dont think he fetches any big prize. So trading him for a lower tier prospect shouldn't be that difficult. We just have to accept that's what we'll get for him.