It's an offer made to a restricted free agent. If the player accepts the offer, he plays for his team for one more season before becoming an unrestricted free agent the following off-season. I think. That could be completely wrong.
Oh, I see. That's kind of weird. I thought Sasha picked up a qualifying offer before the season began. Can you have two qualifying offers in a row? Btw, look at Luke's contract. That's a contract year player for you. This is a perfect example of why I'm hesitant on giving Sasha a long term deal
Basically, at the end of a player's rookie contract, the team can make the Qualifying Offer, which is like a one year extension of the rookie contract. The qualifying offer is just that, an offer. Look at the Warriors and Mickael Pietrus last season. Pietrus' rookie contract was up but the Warriors did not want to re-sign him to a long term deal so they picked up the option on the qualifying offer at the beginning of the off-season. Pietrus spent the whole off-season trying to get a deal done or a S&T. He was still a restricted FA so the Warriors had the rights to match any contract made to him and kind of cock blocked him out of a big contract. Eventually, Pietrus realized that he couldn't get the contract he wanted so he did accept the qualifying offer that the Warriors offered several months before. In doing so, Pietrus rookie contract was extended one year, and he got the appropriate salary raise that comes with that. When a player accepts a qualifying offer that also means that the following off-season they will be an unrestricted free agent and can sign with any team they please while the team they were previously affiliated with has no power to influence his signing.