An England goal for Vardy, ending a two-month drought, has given the Foxes a timely boost ahead of their trip to Vicarage Road.
A two-week break from Premier League action has brought good news and bad for flagging champions Leicester City, who visit Watford on Saturday.
A 2-1 defeat at home to West Bromwich Albion sent Claudio Ranieri's men into the international break just two points above the relegation zone and with injury issues piling up.
But an England goal for Jamie Vardy, ending a two-month drought, has given the Foxes a timely boost ahead of their trip to Vicarage Road.
"It was important for him and important for everybody to score," said manager Ranieri.
"Of course he never spoke about it, but I know goalscorers always wants to score. Now we'll see a new Vardy."
Goalkeeper Kasper Schmeichel (broken hand) and close-season signing Nampalys Mendy (ankle) remain out and key midfielder Danny Drinkwater is a doubt with a rib injury.
But while Drinkwater was sitting out England's games against Scotland and Spain, Vardy was scoring for the first time in 15 games in the 2-2 draw with the Spaniards at Wembley on Tuesday.
Having being dropped for his side's last two Premier League games, the talisman of last season's title triumph is set for a recall.
"Yes, I think he will have a run of games now," said Ranieri. "He can play normally now."
Vardy went 14 games for club and country without a goal after scoring for Leicester in their 4-1 defeat at Liverpool in September.
Vardy said: "It's just always good to get that goal. That one is in the back of the net now and hopefully I can kick on and start putting more away.
"The gaffer (manager) spoke to us, the strikers. The way we play, we can't get all of us on the pitch and that's just football.
"That's how it is. If I'm on the bench then it's up to me to make an impact if I come on."
Five defeats in their opening 11 games have left Leicester's title defence effectively over and playing second fiddle to their first ever Champions League campaign.
They are closer to the bottom three than the top six, but Vardy has played down fears about a season of struggle.
"There's no concern at all," said the 29-year-old, whose side are on the brink of the Champions League last 16 ahead of Belgian side Club Brugge's visit on Tuesday next week.
"We know that compared to last year we've played a lot of what you would call the big clubs early on, whereas it wasn't the same last year.
"Although we know that we are where we are, we know that we can get out of it and we need to start that this weekend."
Watford go into the match looking for a reaction following a heavy 6-0 loss at Liverpool last time out, but they have been boosted by positive news on the fitness of key players Sebastian Proedl and Heurelho Gomes.
Defender Proedl missed the trip to Anfield with a groin injury, while veteran goalkeeper Gomes was substituted due to a heavy knock, but Walter Mazzarri has revealed both are now fit.
"Gomes is back so we are happy," said the Watford manager. "He is a player with incredible experience and every time he's on the pitch he gives massive confidence to the whole team.
"Prodl is back, too, and I hope that will help get the confidence back to (how it was) before we played Liverpool.
"When you play against teams like Liverpool, if you don't have the complete squad it is very difficult. Before Liverpool we were playing very good and weren't conceding."