Southampton could secure yet another free signing this summer as one of their transfer targets has now triggered a contract clause that has made him a free agent. Russell Martin has already welcomed Adam Lallana and Charlie Taylor for free, joining following the end of their Brighton and Burnley contracts respectively. At 36 and 30, Lallana and Taylor bring with them a wealth of experience which will be invaluable to a relatively young Southampton squad. Taylor Harwood-Bellis’ £20 million transfer aside – a deal agreed last summer subject to promotion – Southampton have been making some shrewd…