There is a growing level of worry within the Cleveland Cavaliers‘ organization about first-year coach David Blatt and his ability to reach the team, according to league sources.

Sources told ESPN.com that there is rising concern in team circles about the level of response Blatt is getting on the floor, with Blatt himself acknowledging that the Cavaliers “lost our energy and we lost our competitiveness” in Sunday night’s embarrassing home loss to Detroit.

The Cavs would naturally prefer not to be forced into making an evaluation of their new coach just 30 games into Blatt’s NBA career, cognizant of the fact that the job has quickly evolved into a much different job — after LeBron James stunningly decided in July to return to his home-state team in free agency — than it was when Blatt was hired away from Israeli power Maccabi Tel-Aviv in June with no NBA experience.

But the Cavs’ effort level, especially defensively, is eroding noticeably, raising the volume on questions about just how much the locker room is listening to the 55-year-old Boston native, who has enjoyed tremendous success internationally but still began this season as a relative unknown to NBA players.

Cavs owner Dan Gilbert has proved in the past that he’s unafraid to make coaching changes, dismissing Mike Brown last May with three fully guaranteed years left on Brown’s contract in his second stint as Gilbert’s coach. Yet it should be noted that Blatt was hired in the summer largely at Gilbert’s behest after Cleveland made unsuccessful runs at a number of high-profile college coaches, including Kentucky’s John Calipari, Connecticut’s Kevin Ollie, Kansas’ Bill Self and Iowa State’s Fred Hoiberg.‎

Blatt was indeed asked Sunday at his postgame news conference if he is worried himself that he might be losing control of the team. He responded: “I’m not concerned about that at all. I’m more concerned with how we’re playing.”

Just in the last two weeks, Cleveland has suffered home losses by 29 points (to Atlanta on Dec. 17) and 23 (Sunday’s defeat to Detroit without injured starters Kyrie Irving and Anderson Varejao).

Whispers about the lack of attention various Cavs players are paying to Blatt during some timeout huddles, as well as their apparent preference to communicate with Cavs assistant and former NBA player Tyronn Lue, have been in circulation for weeks. And James acknowledged recently that he did not formally request permission to assume the bulk of the Cavs’ playmaking duties, which triggered Cleveland’s eight-game winning streak earlier this month.

“No, I can do it on my own,” James said of his role change. “I’m passed those days where I have to ask.”

After the eight-game winning streak pushed the Cavs to a mark of 13-7, they are just 5-5 over the past 10 games. During that span, Cleveland ranks 27th in the league in defensive efficiency, 28th in field goal percentage defense and 26th in 3-point percentage defense, according to ESPN Stats and Info. The Pistons made a franchise record 17 3-pointers Sunday night.

The Cavs, it must be noted, are dealing with some lineup upheaval after Varejao was lost for the season last week to an Achilles tendon tear. Star guard Irving, meanwhile, has missed the past two games recovering from a hyperextended left knee and could miss more time as the team lets him recover from an injury he initially suffered on Dec. 11.

The Cavs are 18-12 and placed fifth in the Eastern Conference heading into Tuesday night’s rematch with the Hawks in Atlanta, which happens to coincide with James 30th birthday.

“You know, we’re going through a few things right now,” Blatt said Sunday night. “We’ve lost some pretty important players. … At that point that you have to be more competitive, and more determined, and fight your way through that or else this happens. It’s not an excuse, it’s just an explanation for your question. That’s the reality of it. We didn’t fight enough to battle the difficulties that we’ve had.”