The Dutchman was appointed last summer after Mauricio Pochettino left for Tottenham and a host of players followed him out the exit door.
The likes of Adam Lallana, Rickie Lambert, Luke Shaw, Dejan Lovren and Calum Chambers left St Mary's at the end of last season, prompting many pundits to tip Southampton for relegation, but Koeman resurrected the south coast club who currently sit seventh on the Premier League table.
Of Koeman, 1976 FA Cup-winning manager McMenemy said: "Yes, he should win [manager of the year]. He's got my vote.
"Half the team walked out the door last year and something had to be done quickly. The best appointment they made was Ronald Koeman.
"He used all his connections and experience to get the right people in. He is a top man, the manager."