Hearts striker Lawrence Shankland has returned to training after a mystery illness kept the reported Rangers target out of the weekend’s matches. Scotland international Shankland, 28, missed the Jambos’ weekend win over Spartans due to the issue which had prevented the 18-goal hitman from training last week. Hearts boss Steven Naismith insisted the issue was related to the Hearts striker’s health as Rangers transfer rumours began to take hold. The fact Shankland never played against Spartans ensures that the striker isn’t cup-tied should a move to Ibrox materialise later this month. Lawrence S…