Lee Sharpe has doubted Louis van Gaal's ability to force a new era of success at Manchester United without a physical and vocal presence in the team.
The Dutchman is widely expected to adopt the 3-5-2 formation which saw his Netherlands side secure a third-place finish at this summer's World Cup.
Having already lost veterans Rio Ferdinand and Nemanja Vidic, Sharpe, who played with Steve Bruce and Roy Keane during his spell at Old Trafford, says that Van Gaal will need to recruit a leader to accomodate his formation.
"To play that formation there will be a few changes over the summer – and most probably defensively," he told Sky Sports News.
"If he's going to play three centre-halves, then we may need another centre-half or two.
"[Chris] Smalling, [Jonny] Evans, [Phil] Jones are all good players but they probably need a leader or captain in there to shepherd them."
The Red Devils kick off the new Premier League campaign by hosting Swansea City on August 16.
