The England striker was a substitute for Saturday's 3-1 win over Palace and has now failed to score in his last 10 appearances for club and country
Vardy, who scored 24 goals in last season's title-winning campaign, came on as a second-half replacement as Ahmed Musa, Shinji Okazaki and Christian Fuchs wrapped up the Foxes' first Premier League victory for over a month
It was the first time since March 2015 Vardy did not start a Premier League game when available but Ranieri wanted to keep him fresh as the Foxes juggle their Champions League campaign having beaten Copenhagen 1-0 last week.
"It's normal because we have to play so many matches
All the matches are important and when you see Okazaki and Musa in training I have to put them on the pitch," Ranieri said.
"It wasn't (because) of injury, if he was injured he wouldn't have come with me on the bench
I don't know if he needed a rest but if I don't have Shinji, Musa and (Leonardo) Ulloa maybe I have to play him but when you have some good players it's right to have a rest.
"Always I tinker, when we play every few days it's important to choose the right player, this time I left Vardy and (Marc) Albrighton out."
Fuchs scored his first Leicester goal with a 25-yard half volley after signing a new three-year contract on Friday and Ranieri joked the Austria international will now look for another extension
He added: "I'm angry with him because he has this quality and only today he scores a goal? Now he wants another three years on the contract to score another goal?"
Yohan Cabaye scored a late consolation for the visitors, who also hit the bar through Christian Benteke, and the midfielder felt the result was harsh
"In some stages of the game we played well but it was disappointing to concede the goal just before half-time but I think overall the score is not a fair reflection on the way we played," he told the club's official site
"We did create chances to score goals but we lost the game in the end and that is the most important thing.
"We won three in a row and have now lost two but it's hard to explain why that happens but we must learn from our mistakes."
Source : PA
Source: PA