United, who are seven points clear of champions Manchester City at the top of the table, head to London with Ferguson planning to freshen up his team after what he said was a lucky 2-1 victory over struggling Southampton midweek.
"Hopefully Jonny trains today, which would give us another defender. That's good news," Ferguson told a news conference.
"I'll make one or two changes tomorrow. Rio Ferdinand will play, definitely."
After surviving a second-half onslaught from 16th-placed Southampton on Wednesday, United will be keen to avoid any slip-ups against 12th-placed Fulham with Ferguson saying defeat against lower-placed teams had cost them dearly last season.
"Every game gets treated the same way, you saw the effort Southampton put in on Wednesday, it is a reminder to us that you get three points for every game not just for beating the top of the league," Ferguson said.
"Last year we lost at home to Blackburn Rovers [who were eventually relegated] and it is quite easy to maybe say that cost us the league."
United lost the title on goal difference to neighbours Manchester City in the final seconds of the last day of the season.
Ferguson is looking to his strikers to drive United's campaign for a 20th league title, saying that if Robin van Persie, Wayne Rooney and Javier Hernandez could net 20 league goals each it could be key.
The league's top scorer Van Persie is already close to the target with 18, while Rooney scored twice against Southampton to reach nine and Hernandez is on eight.
United are glad to be playing away from Old Trafford this weekend where the pitch has been suffering after some heavy rain.
"It's not good... it's worn out a bit to my mind," Ferguson said. "We are doing our best to get it better for the Everton game [on February 10].
"We've got the lights on all the time, hopefully there will be better weather, we've got a bit of sun at the moment... it's much milder. The more light we get the better for the pitch. We're hopeful."
Manchester United have 59 points from 24 games with second-placed Manchester City on 52 and Chelsea, in third, on 46.
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