It is believed that Mazda is working to upgrade the Mazda 6 and have it release as a 2017 model. If that is the case, it is highly possible that the Mazda 6 will not be coming with the new engine this time around.
The new engine was introduced alongside the new Mazda CX-9 model. The new 2.5 liters turbocharged four-cylinder engine will be offering about 227hp and 310lb ft of torque. According to Mazda, the engine was designed to be compact so that it can be fitted into any other Mazda model.
While it would be nice to see the engine under the hood of the upcoming Mazda 6, it does not look like Mazda will have the time to do so. Adding in the new engine will mean that Mazda will have to do a few more testing and modification and that means it might not make it in time.