Actually, a court would NEVER grant specific performance for a contract of employment.
If he was to accept an offer (if one has even been made), no legal action would ensue. Last thing St Kilda would want is prolonged press coverage over the preseason and into next season. Especially one where they have only minimal prospects of minimal damages. Only thing that would save St Kilda is a clause to the effect of "you shall not work as a senior AFL coach within twelve months of leaving St Kilda' - but Lyon should get a new manager if he ever agreed to such a thing!