LeBron James and Kevin Love can only watch as Golden State’s Andre Iguodala throws it down with Draymond Green looking on during the Warriors’ win in Cleveland Monday night. (Michael Hickey/Getty Images)

CLEVELAND — At their best, the Cleveland Cavaliers are still one of the league’s best teams. They showed it at times Monday night, even in losing for the second time this season to the Golden State Warriors. Few teams are able to make the Warriors uncomfortable, as the Cavaliers can, and no other team has the best player in the world, as LeBron James is.

The Cavaliers are 36-5 in the Eastern Conference playoffs over the past three seasons, cruising their way to a trio of Finals appearances against Golden State. If the first three months of this season are any indication, however, doing it again won’t be the cakewalk Cleveland is used to.

“We just want to continue to get better,” James said, and there is plenty of that to do. It was less than a month ago that the Cavs arrived in Oakland to face the Warriors on Christmas Day having won 18 of their previous 19 games, and looking exactly like the presumptive Finals representative they were supposed to be.

Then Cleveland lost that game, beginning a downward spiral now clocking in at eight losses in 10 games, the latest of which was Monday night’s 118-108 disappointment, the Cavs’ fourth straight defeat. The streak began with a rout in Minneapolis at the hands of the Timberwolves. Then they got blown off the court again, this time in Toronto by the Raptors on Thursday, before giving up a 22-point lead in a loss to the Pacers on Friday.

It’s not a coincidence that these struggles have coincided with Isaiah Thomas’s return to the court after missing the first two-and-a-half months of the season rehabbing a hip injury. So much time away was inevitably going to lead to rust, and Thomas has exhibited a lot of it through his first five games. That Monday’s performance (19 points on 7 for 21 shooting and four assists) was an improvement from the way he played in Minnesota and Toronto, when he combined to make just six of 26 shots and score 13 points, is indicative of just how far away Thomas is at this point.

“My body feels good,” Thomas said. “I’ve just got to get in shape … I’ve got to get my legs back. Especially when I get a little winded, my legs get even heavier. So I’ve just got to keep pushing, keep working and it’ll come back.”

But even when Thomas does get back — and that is assuming he is able to — he isn’t going to fix the Cavs’ biggest problem and that’s their porous defense. Giving up 118 points to Golden State isn’t actually that bad, but on the season the Cavaliers rank second to last in the NBA in defensive rating, an unthinkable position for a title contender.

Some of that can be fixed by effort. Then again, Cleveland has several players — Thomas, Kevin Love, Kyle Korver, Dwyane Wade — who can’t consistently defend at a high level regardless of how hard they try.

Then there are the issues with the Cavs’ heavily counted on role players, namely Jae Crowder, J.R. Smith and Tristan Thompson. Crowder is not the same player in Cleveland that he was in Boston, shooting under 40 percent from the floor and just over 30 percent from three. Smith looks nothing like the dynamic scorer he once was, and is also shooting below 40 percent.

Thompson, meanwhile, has been demoted from the starting lineup, and hasn’t been nearly the same kind of high-energy, impact player he’s been in the past.

So, the Cavaliers remain the favorite to get out of the East this season, but that position is not nearly as unassailable as it’s been ever since James came back to Cleveland.

Not that they see things that way.

“Yeah,” Coach Tyronn Lue said flatly, when asked if his team remains the best in the East, despite having the third best record.

Why?

“Because we’ve got the best player in the world,” Lue said. Not a bad answer. But even he circled back and qualified his remarks.

“We’re not playing the best right now,” Lue said, “but we will be the best team in the East.”

How they’ll get there is an open question. There will be talk of trading the Brooklyn Nets’ unprotected first round pick in this summer’s draft, the true centerpiece of the trade that sent Kyrie Irving to the Boston Celtics — the Eastern Conference-leading Boston Celtics — in an attempt to fortify Cleveland’s chances.

Yet the specter of James leaving as a free agent this summer continues to hang over the franchise, making such a move highly unlikely even though it could give the Cavs the kind of bridge to the future Irving himself once represented as the top overall pick in the 2011 draft. Even if the Cavaliers make the pick available, there’s no indication of what it would get them. DeMarcus Cousins was expected to be on the block this season, but the New Orleans Pelicans are in the playoff picture and won’t be moving him. Same for DeAndre Jordan, whom the Los Angeles Clippers were expected to trade before they moved back into the playoff picture out West, as well.

Meanwhile, the teams around the Cavs — specifically the Celtics and the Toronto Raptors — are stocked with assets and young players to swing in deals themselves. It may not be the Cavs, but one of their chief rivals that makes a significant addition at the deadline.

Cleveland’s best chances at improvement are internal. Thomas could round into form and give James another offensive fulcrum to play off while propping up the offense when he sits. Those floundering role players may step up and provide a lift. The Cavs could even make some strides defensively — though that one, by far, seems most unlikely.

But there’s also the chance that none of those things will happen. Because of the presence of James alone, it may not matter. He could find himself back in the Finals for an eighth straight time, and his Cavaliers could be meeting the Warriors for a fourth straight year.

For the first time since returning to Northeast Ohio, James is going to have a fight on his hands for that to play out.

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