Graeme McDowell gave a warning of what Europe's players can expect when the Ryder Cup starts in sports-mad Chicago on Friday.

And he also gave the broadest of hints as to which eight he thinks will be involved as Jose Maria Olazabal's side open the defence of the trophy he won so dramatically at Celtic Manor two years ago.

''There's a world of difference between playing in front of your home fans and playing in front of the US fans,'' the Ulsterman said.

McDowell made his debut in the 2008 defeat at Valhalla, but then had compatriot Rory McIlroy as his partner in Wales and is expected to team up with him again this week.

''Putts that drop in front of your home fans are like a bomb going off - and putts that go in this weekend will be like someone's got the silencer on. It's like a muted applause.

''I remember Valhalla. The 14th was a very big natural amphitheatre and one of the most intimidating holes as a European.

''You knew when somebody birdied - you could hear it reverberating around the course. ''I think 17 (another par three) is going to have the same effect this week.

''There's something interesting about missing a putt and having the cheers go up. That's something we are not used to as golfers, but it's something you've got to accept this week and I'm looking forward to it.''

That said, McDowell also believes - and hopes - ''the days of hostility I think are gone'', but with the course set up for low scoring he added: ''I think Davis (US captain Davis Love) wants birdies and eagles to get the crowd fizzed up''.

Seven of Europe's 12 have experienced an away match before, including 43-year-old Scot Paul Lawrie, who returns to the side 13 years after his debut in Boston, the rowdiest match in cup history.

Lawrie hit the opening shot of the match that week and there was the first indication yesterday he will be involved in Friday morning action again.

The former Open champion was sent out for practice alongside McDowell, McIlroy and Sergio Garcia, while 2008 partners Justin Rose and Ian Poulter were with Lee Westwood and Luke Donald, who two years ago thrashed American top pair Tiger Woods and Steve Stricker 6&5.

That left Francesco Molinari, Peter Hanson and Martin Kaymer, all of whom were debutants at Celtic Manor, with Belgian newcomer Nicolas Colsaerts.

McDowell hinted they may not enter the fray until the afternoon fourballs unless someone really shines in the three days of practice.

''The established partnerships are fairly obvious - myself and Rory, Poulter and Rose, Donald and Garcia, perhaps a Westwood and Lawrie.

''You can pretty much predict our first eight players Friday morning. You don't need me to tell you that.

''Will we be that predictable? Who knows?''

Having lost away and won at home perhaps it was no surprise to hear the 2010 US Open champion making the Americans slight favourites.

It used to be thought that Europe always held the upper hand in camaraderie because they travelled together more, but according to McDowell ''the American team have got a lot more than they have ever had before.

''I feel like their team is a lot more close-knit than it ever used to be, so that advantage has kind of gone to a certain extent''.