The world and European champions' record marksman, with 53 goals in 86 appearances, broke his leg at the Club World Cup in December 2011 and struggled for goals and fitness after returning to action at the start of this season.
The 31-year-old Barcelona forward scored a fine goal in this month's Champions League comeback against AC Milan and struck again against Rayo Vallecano in La Liga at the weekend when he also assisted two goals for Lionel Messi.
"The change in Villa is the joy, the optimism he exudes at the moment," Spain coach Vicente del Bosque said on Thursday.
"Fortunately he has recovered and we have the best goal scorer in Spanish football back," he told a news conference previewing Friday's game against Finland in Gijon.
"He felt himself a bit sidelined because he wasn't playing as much but you have to take into account that he was coming back from a serious injury.
"I hope that now he will give us what we expect of him."
Villa was an automatic starter for Del Bosque at the 2010 World Cup but without him at Euro 2012 the coach alternated between playing Fernando Torres as a lone striker and using Cesc Fabregas as a roving forward.
Villa's return adds another attacking option to a team who have swept all before them since winning Euro 2008 when he was top scorer in the tournament with four goals.
"I have played a few games from the start recently and the team has managed to win so I am pleased with that," the former Valencia player told Thursday's news conference.
"I have been looking for this consistency for a long time.
"What I want is to enjoy myself and finish the season well, which has had plenty of ups and downs."
Spain and France, who drew 1-1 in Madrid in October and meet in Paris on Tuesday, are level on seven points at the top of the group after three matches, with Spain in first place thanks to a superior goal difference.