mixing stereo recorded Pianos

[Michael Brauer]

I have a few suggestions.( I'm assumimg you already tried hitting the phase switch without any success)
1-If it's playing within a band and not the focus, just use one side that sounds best in the mix and EQ it, to make up for the low or high side.
2-The other thought is to purchase the partial reverse phase box from little labs. Instead of having a limited choice of in phase or 180°, you can dial in the amount. It's also great for bass when you have a direct and amp to combine.
3-Try a variation of my disco piano sound mentioned in an other post. The combination of compression and mid eq's might bring the "in Phase" sonics out to the front.