Eastwood scored only four goals for City following his £1.5m switch from Wolves and has said he is capable of a lot more.
"I've still got a lot to prove, both to myself and the supporters," Eastwood said to the club website.
"It was a long hard season so I am taking some time out to rest and recover but when pre-season starts it's all business for me.
"Did I show what was capable of last season? Not at all because I don't think I really hit any kind of form throughout the season.
"For me, being in form is not about one good game, you want ten or 12 good games and I didn't do that last season.
"But pre-season training is not far away now so I want to get started, stay injury-free and show what I can do when the season starts."
"For me, being in form is not about one good game, you want ten or 12 good games and I didn't do that last season.
"But pre-season training is not far away now so I want to get started, stay injury-free and show what I can do when the season starts."