Free agency wasn't what Kevin Martin thought it would be.

The former Thunder guard assumed becoming an unrestricted free agent for the first time would be exhilarating, a liberating process in which he, at 30 years old, finally controlled his destiny. But when teams came calling in July, the game suddenly turned serious.

“Everybody says free agency is fun. It wasn't fun for me,” Martin said before his Minnesota Timberwolves hosted the Thunder on Friday night. “That's a big decision to make for yourself and for your family. I thought it was going to be fun. It was stressful.”

Martin said he had an idea last year would be his only season in Oklahoma City. There were moments throughout the year, he said, that confirmed that reality.

“A lot of times the NBA is about the business,” Martin said. “You saw that firsthand with James Harden. Sometimes both sides have to make tough decisions.”

The Thunder faced an increasing payroll that, even without Martin, is close to exceeding the tax threshold this season. Martin, meanwhile, sought security. The two simply didn't mix.

Martin ultimately agreed to a four-year, $28 million contract with Minnesota, although the Thunder later worked out a sign-and-trade that netted OKC a $6.6 million trade exception. Milwaukee, Memphis and New Orleans also expressed interest.

“It was a pretty hectic first 24 hours,” Martin said of July 1, the first day teams could contact free agents. “Besides leaving school, that's the biggest decision of my career; especially at the age of 30, that could be your last free agent (contract). I did my research. I did it wisely with teams, and I felt like this was the perfect spot, ideal. Just what they need.”

Martin expressed confidence in Reggie Jackson and Jeremy Lamb being able to fill the void left by his departure.

“With them playing behind (Kevin Durant and Russell Westbrook), if you can, in the second half, hit open shots you're going to excel in that role,” Martin said.

The key, according to Martin, is embracing the role.