The 28-year-old's name was notable by its absence when New Zealand Cricket (NZC) released its list of 20 players to be offered contracts for the forthcoming season.
His axing surprised many, including Otago coach Mike Hesson, who described his omission as "hugely disappointing".
While he would lose financially, the axing did not change anything else, Butler said.
"Obviously, it took me by surprise at the time. But, to be honest, it does not really change anything," he said.
"Whether I have a New Zealand contract or not, my whole focus is about performing well for Otago at the start of the season and then I have to be picked.
"In essence, it is only the financial security thing which is disappointing. It makes no difference to the way I approach the season."
Butler received the news on Friday when he travelled to Christchurch with Hesson for his NZC performance review.
"The review went really, really well, and at the end of it I got that news dumped on me by Geoff Allott [NZC general manager].
"But with how well my review went, I certainly don't feel like I'm not in their thinking for the teams."
Butler did not believe a run of injuries counted against him.
Rather, it came down to ranking points, and because he did not have a test ranking he was not able to accumulate enough points to warrant a contract offer.
"You can't be bitter. Sport is my life and I love playing cricket. There are always going to be ups and downs."
A back injury forced Butler to return home from England last month.
He had been playing in the domestic twenty/20 tournament for Gloucestershire and was replaced by Otago team-mate Aaron Redmond, who also missed out on a national contract.
"I'm fine now. I'm back home, back training at the gym. It is just a process of making sure I do it right. But going well, it is probably going to take me another three or four weeks before I can get into cricket skills."
