OKLAHOMA CITY — The first big dose of small-market reality has hit the Oklahoma City Thunder.

Before the Thunder even played their first real game following a trip to the NBA finals, the franchise parted ways with Sixth Man of the Year James Harden in a trade with the Houston Rockets, fracturing the team's core and substantially changing the second unit.

"We made several efforts to try to make this work," general manager Sam Presti said at a news conference Sunday.

"I think there's a point in every negotiation where you start to realize where things are lining up, and at that point you have to play the hand that you're dealt. I feel like as an organization, we've made some tough decisions. This one was right up there with them."

Presti said the Thunder made what was supposed to be a final offer on Friday, then approached him one last time before pulling off the trade Saturday night — making sure that Harden realized he could be dealt if he didn't accept.

But Harden, who developed into one of the league's most dynamic shooting guards after being the No. 3 pick in the 2009 draft, still wanted more.

Oklahoma City already had All-Stars Kevin Durant and Russell Westbrook plus NBA blocks leader Serge Ibaka inked to long-term, eight-figure deals and — even with an arena upgraded by taxpayer funds that's sold out for every game — wasn't willing to offer him a maximum contract.

Presti said the Thunder made an "extraordinary effort" to keep Harden and side-stepped whether the team tried to low-ball Harden.

"That's for other people to determine, I suppose, and ultimately we'll live with that. We understand what we were able to do, and what we did, and the significance and the importance it made, especially considering the commitments that it would have taken our payroll to," Presti said. "Our ownership group was absolutely behind that effort."

Harden said Sunday he expects to sign a long-term deal with Houston before the regular season starts. He was saying the same thing about Oklahoma City when training camp began.

Durant, Westbrook and Ibaka all took marginally less than they could have demanded on the open market to stay in Oklahoma City but Presti suggested "the term sacrifice gets thrown around maybe too loosely." He said the Thunder didn't begrudge Harden for rejecting their offers.

"We're not going to judge anybody. We're not going to put anything on anybody," Presti said. "We're going to do the best thing for the franchise. In a lot of cases, in most cases, the players are going to do the best things for them. You hope that those things overlap, and we've been very fortunate they have overlapped in a lot of cases."

The Thunder simply aren't in a position to spend like the Miami Heat, who went over the cap to add Ray Allen and Rashard Lewis after beating Oklahoma City in the finals, or the Los Angeles Lakers, who added All-Stars Steve Nash and Dwight Howard to a lineup that already featured Kobe Bryant and Pau Gasol.

"I think we all know that James Harden was a big part of their team. That goes without saying. He was a big part of why they made it to the finals," the Heat's LeBron James said. "They got a couple pieces back that are really good as well. But we don't know how it changes their team until they actually get out there."

Presti said the Thunder got more for Harden because they dealt him early enough that Houston could re-sign him before a Wednesday deadline to reach a contract extension.

Oklahoma City received guards Kevin Martin and Jeremy Lamb, two first-round draft picks and a second-round pick in the swap, and also sent Cole Aldrich, Daequan Cook and Lazar Hayward to the Rockets. Presti expects the draft picks to be critical to rebuilding quality depth at a low price.

The departure of Harden and, to a lesser degree, Cook and Aldrich rattles Oklahoma City's second unit that already lost veterans Derek Fisher and Nazr Mohammed in free agency. Backup point guard Eric Maynor will return after missing most of last season with a knee injury, with power forward Nick Collison the only other holdover from the second five.

First-round draft pick Perry Jones III and free-agent acquisition Hasheem Thabeet figure to move up in the rotation now.

Presti said the Thunder still consider themselves championship contenders — but so does every team in the league when the season starts.

"With the group that we have, they've been through a lot together and they've won a lot of games together. So, for us, of course we're always going to feel like we've got a chance to do good things," Presti said. "However, I would also add that it's never been our approach to do a lot of talking about what it is we're going to do or who we are.

"I think we're at a point as a franchise where we have to do what we say."