Boss Gianfranco Zola was left to rue a lack of a cutting edge as the Hornets were stung 1-0 at the King Power Stadium on Thursday.
Leading scorer Deeney is back after a one-game suspension following his dismissal in the last-day drama against Leeds and his return makes Zola confident of progressing.
He said: "I'm sure we can do it. I am confident because we have goals in our side and we will have Troy Deeney back from suspension.
"I will have different options on Sunday, I'll [evaluate] all the players and will find the best solution."
Matej Vydra has failed to score in his last 12 league matches but could still partner Deeney in attack.
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