The biggest move was owners allowing teams that are not more than $4 million over the luxury tax line to use the full mid-level exception of $5 million, according to multiple reports. That $4 million window makes a world of difference for the Heat and should allow them to:

• Use the entire $5 million mid-level exception in free agency without having to use the amnesty clause on Mike Miller to waive him and get his contract off the books.

• Use the entire mid-level exception on a free agent and still be able re-sign restricted free agent Mario Chalmers and rookie point guard Norris Cole.

• Keep Miller and Chalmers, sign a $5 million free agent, sign Cole and still be able to tack on veterans at the NBA minimum. Perhaps players like Grant Hill, Michael Redd, James Jones or players who are waived by the via the amnesty clause elsewhere.

As of just a few days ago, the way the proposals were set up, it appeared certain the Heat would have to use their amnesty clause on Miller immediately just so they could add to their roster. The Heat currently have $65 million in salaries for this season before signing Cole. At the moment, they also have no point guard under contract, applying pressure to re-sign Chalmers as well because the free agent point guard market is thin.

But they couldn't afford to do both and stay under the luxury tax line, which is expected to be right about where it was last season at $70.3 million. The owners wanted to make any team that was over that line unable to use the full mid-level exception, including if using that money pushed a team into the tax zone. The Heat are planning on using the mid-level on a center, with their top target believed to be free agent Sam Dalembert.

This appeared to leave them little choice but to release Miller to free up the majority of the $5.4 million he's owed this season so they could make the needed signings. Or at least have the option to do so. There's a reason why Miller put his house on the market recently.

According to league sources, the Heat had planned to waive Miller and had let him know through back channels so he could prepare. This information was not all that secret -- teams in need of shooters were already doing background research on Miller and considering bringing him in. Miller had a number of suitors when he was a free agent a year ago, including the Chicago Bulls.

He may not want to take his house off the market just yet, though. With the expected luxury-tax changes, the Heat still may end up waiving Miller with the amnesty clause before next season to allow them to free up enough space to use the mid-level exception again. But considering they will be paying Miller either way, they would much prefer to have him on the roster and see if offseason surgeries to his thumb and shoulder will allow him to return to his form from two years ago, when he was one of the best shooters in the league.

Brian Windhorst covers the Miami Heat for ESPN.com.