Think about your centers . . . are they related to your curriculum? Are you required to do them. If you initiate the Daily 5 as the Sisters recommend, you really don't need centers. Developing the independence to do read to self, work on writing and word work, along with read to someone and listen to reading, take the place of centers that you have to create.
Couldn't your curriculum's lessons be worked into your mini-lessons? Do you do CAFE--it really is easy to fit most good lessons into the strategies.