Perhaps the biggest reason this NBA offseason has been so active is the Golden State Warriors, who have raised the bar considerably across the league. It's no longer enough to have one or even two stars. You need stars who fit. You need multiple versatile, No. 1-type options. You need a position-less, athletic defense. You need all that for the best shot at the champs, who sport 5/11 odds to win it all again, return everyone of significance and added two more 3-point shooters, Nick Young and Omri Casspi

Here are the top five contenders to keep the Warriors from winning their third NBA championship in four seasons, with their 2017-18 title odds and SportsLine's projection for their victories next season.

1. Cavaliers | Odds: 7/2 | SportsLine: 54.2 wins

They were unable to trade for Jimmy Butler or Paul George, reportedly because they couldn't find takers for Kevin Love, but they're still the biggest threat, though the margin between Cleveland and the next two teams on this list has shrunk. 

Cleveland has a tougher challenge in the East next season because Boston got better, but barring injury, the Cavs are the clear favorite to come out of the East. That's fortunate for them, because if they flipped conferences and had to get through Houston, San Antonio and/or Oklahoma City in some order, LeBron James' chances of advancing to an eighth straight NBA Finals would be in real jeopardy. 

If we end up with a Cleveland-Golden State matchup in the Finals for a fourth straight year, the Cavs have done nothing to close the gap. But they still have James and Kyrie Irving, and they were the only team to take a playoff game off Golden State, and had the Warriors on the ropes in Game 3 of the Finals. They still look like the second-best team in the league, and Vegas agrees

2: Thunder | Odds: 30/1 | SportsLine: 46.5 wins

If you're thinking OKC is just a nice story, like "good for them, they gave Russell Westbrook some help," you might be underestimating this club. What George brings to the offense is obvious from a scoring/play-making standpoint, but it's the defense that really makes OKC the second-biggest threat. If not for the LeBron James factor, the Thunder would be the biggest threat. 

Look at OKC's likely starting lineup: Westbrook, George, recently re-signed Andre Roberson, Patrick Patterson and Steven Adams. Adams and Roberson are elite defenders, and George is not far off. Patterson is a versatile big who can guard on the perimeter, and his shooting will allow Roberson (a terrible shooter) to stay on the floor in more lineups without compromising spacing. Westbrook also can wreak defensive havoc -- even if he won't always take the challenge to stay in front of the league's best point guards for 40 minutes -- when engaged.

That is a really versatile lineup that can switch all over the perimeter, the first key to slowing down the Warriors. Behind them, Adams had the fourth-best defensive rating in the league last season. He's terrific. A true athletic paint protector. That allows those athletic perimeter defenders to run Golden State's shooters off the 3-point line, knowing Adams is behind them. 

Are the Thunder going to stop the Warriors? It's highly unlikely anybody will completely stop them. But they definitely have lineups that can own stretches, that can get three or four big stops in a game-deciding run, that can at least force Golden State to earn its points. 

3. Rockets | Odds: 20/1 | SportsLine: 55.2 wins

The Rockets won 55 games last season and added Chris Paul. If they played the Thunder in a series, Houston might win, but the Rockets don't match up as well with the Warriors because they lack OKC's defensive punch and versatility. 

But they're going to flat-out score with all those shooters around Paul. Outscoring the Warriors is really tough, but with Paul and James Harden, Houston has the only back court in basketball as good as -- or maybe even better than -- Stephen Curry and Klay Thompson. Without Paul, Houston made more 3-pointers than anyone in the league last season and averaged 115.3 points, just behind Golden State's 115.9 for tops in the league. 

Imagine a possession with Paul at the top of Mike D'Antoni's offense with Harden, Ryan Anderson and Eric Gordon. Imagine the space he's going to have to create with defenders attached to those shooters. As for Paul and Harden co-existing as ball-dominant players, they'll have to figure that out when the game slows down -- though D'Antoni's teams rarely slow it down. 

Houston is going to run, and when that's happening, it's akin to a defense with versatile players who can guard any position. The more players who can initiate early offense and create for others in the open court, the harder you are to defend. Don't get too hung up on who does what and when; Houston has multiple guys who can open up scoring opportunities. And against the Warriors, you're going to have to put a lot of points on the board. 

When you can score and shoot 3-pointers the way Houston can, you have a chance against anyone. 

4. Spurs | Odds: 12-1 | SportsLine: 52.4 wins

We all remember how the Spurs had Golden State down 25 in Game 1 of last season's Western Conference finals before Kawhi Leonard left because of an ankle injury. They've shown they can play with Golden State, and added Rudy Gay for more scoring. 

It's so tough to put anyone ahead of the Spurs because they always seem to figure out a way to compete with anyone. But looking at this team, it is going to have a tough time scoring with the Warriors over a seven-game series. The Spurs beat Houston in last season's playoffs, but if they match up with Paul on board, the Rockets are the pick here in a seven-game series. No doubt that prediction goes down in flames when the Spurs again find a way to win 60-plus games and find their way back to the conference finals. 

Still, even if this happens, it's tough to see how they're more equipped to beat the Warriors over seven games than the Thunder, Rockets or Cavs. They just don't have the firepower. 

5. Celtics | title odds: 10/1 | SportsLine: 54 wins

Maybe Danny Ainge knows the Celtics can't beat the Warriors, which is why he's pretty clearly continuing to build his team with a down-the-road approach. But the Celtics have given Golden State problems the past few years. A lot of that was because of their ability to guard on the perimeter, and much of that left with Avery Bradley. If one defender is best equipped to stop or frustrate Curry in a game, it might be Bradley. 

But Boston can still put a really versatile defensive team on the floor with Jae Crowder, Marcus Smart and Jaylen Brown. And the Celtics have a much better chance of scoring with elite teams with the addition of Gordon Hayward, Marcus Morris and No. 3 overall pick Jayson Tatum -- who has solidified his rep as a polished scorer in summer league play -- next to Isaiah Thomas

All told, Boston probably isn't a real threat to Golden State, but it did close the gap on the Cavs in the East. In a hypothetical Eastern Conference finals matchup between Boston and Cleveland, the Celtics would have a legitimate shot.