The Red Devils open the defence of their crown against Reading at Old Trafford on Sunday. On the evidence of Sunday's Community Shield encounter, Chelsea will provide their usual stern challenge, while Arsenal have been impressive in pre-season despite the loss of Thierry Henry. Many pundits are also tipping Liverpool for their most robust assault on the title since they last won it in 1990. Rafael Benitez has certainly invested heavily this summer, bringing in a host of star names. Tottenham, Newcastle, West Ham, Portsmouth and Manchester City have also been particularly active in the transfer market. Yet Ferdinand believes it will be Christmas at the earliest before it will be possible to judge exactly who has bought well. "Any year is going to be hard to win the league," he said. "The fact other teams have spent a lot of money poses different questions but it also raises questions about them. Will they gel? Will they become better teams? Will their managers be able to cope with having so many players in the squad? Will he be able to juggle? "It is all ifs and buts. We will see when Christmas comes how the teams have dealt with their respective acquisitions and how they are going. "The one thing I do know is that our manager is very experienced in that capacity, so hopefully that will give us the step in front we want." Ferguson is certainly experienced in dealing with troublesome players and had face-to-face discussions with Gabriel Heinze on Monday in a bid to resolve the row over his proposed move to Liverpool. Heinze had pledged to report for duty as ordered by Ferguson and duly arrived at United's Carrington training complex, following a brief break after his Copa America campaign with Argentina. Ferguson was eager to speak with Heinze to establish his intentions after blaming the 29-year-old's agent for talking up a move to Liverpool, something United are implacably opposed to. It was expected Ferguson would restate a position chief executive David Gill verbally advised Heinze's agent of; namely United will not sell any of their players to a major domestic rival, even though Liverpool have matched the Red Devils' stated £6.8million asking price. Heinze has appointed a legal team to assess the validity of the letter Gill signed confirming a figure that would trigger his release. For their part, United insist the note does not override Heinze's current contract, which still has two years to run. It is also thought Gill's verbal clause, which came before Liverpool boss Rafael Benitez made his interest known, was recorded.