When Hayden was on Robert Craddock's show on Foxtel he hinted that he and Taylor never really got on. Taylor was/is chummy with NSW mate, wanted a right handed partner and pushed for Slater to play ahead of Hayden. Hayden got frustrated, Slater more than earned his spot so basically Hayden was frozen out until Taylor retired. Having said that, Slater and Taylor were a great pair and if Hayden still holds a grudge this far on then he needs to get over it.
He basically said this in his autobiography too, Taylor pushed very hard for Slater at the expense of him.
Reading between the lines, it seems Hayden was upset that it even came down to a "bat-off" in the first place. Hayden had been churning out squillions of runs, and seemed to view Slater as a bit of a johnny-come-lately who was unfairly elevated to equal status by Taylor.