Felt cannot officially recommend using any trainer to which a frame can be mounted, as intense pedaling efforts can cause side load on the seat stays and potentially cause breakage. If the frame breaks, then this would NOT be covered under warranty.
Felt knows that many riders will use a trainer either to warm-up before a race, or to perform a workout in the comfort of their own home. Anytime a bicycle is ridden on a stationary trainer, it must be done correctly and the rider must be aware that their bicycle was not designed for such an activity. Every trainer is different, and countless factors can affect the forces being put onto your bicycle frame, including but not limited to how hard it will be ridden, how often, or even the weight of the rider. Trainers featuring side-to-side movement are typically better equipped to handle such factors versus rigid/locked models. However, Felt engineers design bikes for the best possible riding experience on the road, and therefore do not compromise this real-world ride quality by making Felt bikes optimal for stationary trainers.