May 16 (Reuters) - Massimiliano Allegri's future as AC Milan coach hangs in the balance as his side visit relegated Siena on the last day of the season on Sunday, still needing a win to clinch third place in Serie A and a berth in the Champions League playoff round. Allegri's players have voiced their support for the coach, who has overseen an impressive revival in the second half of the season with only one Serie A defeat since the winter break. ... More...