Rooney, who has been in superb form this season and scored nine goals in his opening five league games, has not featured since United's 3-1 victory over Chelsea on September 18.
Hernandez was forced off with a dead leg in last Saturday's draw against Stoke City.
"Wayne and Hernandez are fit for tomorrow," manager Alex Ferguson said.
Ferguson said there was further good news on the injury front with centre back Jonny Evans ready to return and defenders Nemanja Vidic and Chris Smalling and midfielder Tom Cleverley close to full fitness.
Liverpool manager Kenny Dalglish has called for his players to be committed but cool in the fevered atmosphere of the 216th Merseyside derby at Goodison Park.
The Reds have played well in short spells this season but the Scot knows it will require more than that to beat their nearest neighbours and closest rivals.
"The most important thing for us is to be confident, composed and have the belief we can win the game," he said.
"It is up to us to get that into our players and get them to believe it.
"We know we have to be totally committed to get the result because if we aren't we won't get anything."
Saturday October 1
12:45 Everton 0 - 2 Liverpool
15:00 Manchester United 2 - 0 Norwich City
15:00 Sunderland 2 - 2 West Bromwich Albion
15:00 Aston Villa 2 - 0 Wigan Athletic
15:00 Wolverhampton Wanderers 1 - 2 Newcastle United
15:00 Blackburn Rovers 0 - 4 Manchester City
Sunday October 2
13:30 Bolton Wanderers v Chelsea
15:00 Fulham v Queens Park Rangers
15:00 Swansea City v Stoke City
16:00 Tottenham Hotspur v Arsenal