The Costa Rican playmaker came on as a substitute to smash in a superb equaliser against Reading in a dramatic 3-3 draw at the Madejski Stadium.
Ruiz had been sidelined for more than a month and insisted that he feels ready to have an impact from the start at Craven Cottage.
He told the club's official website: "It felt great to come back. Especially to come back with a goal and an assist, I feel good.
"Hopefully I'm going to work really hard this week to be with the team for the next game."
Fulham are seventh in the Premier League on the back of a three-match unbeaten run ahead of a home game against fifth-placed Everton next weekend.