Doubt it. If Grundy leaves it's cos he was sold a BS vision by the Dees and they will get him to where he wants to go after wasting a year of his time.
It's not good business to be paying ~$650k for your backup ruck playing reserves just in case Gawn gets injured. You can get adequate backup rucks for nothing every single year.
His a contracted AA ruck with half a dozen suitors who the Dees are happy to keep. Dees hold all the cards in any trade negotiations.