Wouldn't be surprised if this is true, Crewe have lost Ng, Kirk, Pickering, and Wintle over the past year and have probably only recouped about 2,000,000 to 3,000,000 for all of them despite their collective value being almost twice of that.
They don't want to lose another player for cheap again, which is understandable.
500k for a player with one year on their contract is probably fair, but in Crewe's eyes he'll be worth twice that in a year or two so they want to ensure they get as much out of him as possible.
However, if he's refusing to train that tips the scales in our favor.