The 19-year-old has started every league game since arriving on Teesside on a season-long deal from Chelsea.
Both clubs have an option to end the deal in January but Boro have no intention of doing so and it looks like the European champions are also happy to see his development continue at the Riverside.
As well as sending Chelsea a DVD of every match McEachran plays in, Mowbray also produces an individual report on his performance for their first team coach.
"Eddie Newton (Chelsea's assistant first team coach) was at the training ground on Friday and at the game on Saturday," said Mowbray. "He's not Rafa Benitez, of course, but he's telling me the club policy is not to bring on loan players back.
"He told me they have no reason intention of bringing him back. Josh is doing great for us and we obviously hope he can stay, but he's Chelsea's player."
And Mowbray's half-term report to McEachran is that he's done a great job so far - but he wants him to get even better as the campaign approaches its climax.
"He has to push on in the second half of the season," Mowbray said. "He's settled in great and he can drift past players and pick our wonderful passes.
"But if he wants to play in the Chelsea first team and win European cups, he has to have more impact on our games in the Championship.
"I've told him and he understands it. I think he can add that missing ingredient."
McEachran has recently reiterated his desire to remain with Boro for the rest of the season.
Meanwhile, Mowbray does not expect to be busy in the transfer market in when the window open again at the start of next month, especially with Rhys Williams, Muzzy Carayol, Julio Arca and Curtis Main all coming back to fitness.
"We're not really in the market place to add more players in January," he said. "We're going to have some real selection headaches about who's getting left out and who's sitting in the stand as opposed to on the bench.
"So I'm not here looking at trying to get a load more players in January. We're trying to manager the squad, if there are any outs there might be an in.
"If not then the likes of Luke Williams and Adam Reach, who have been on the periphery for the last month or two, will probably get an opportunity. They're talented young boys.
"So I'm not sitting here thinking, 'Let's go and buy some players'. The squad have coped well this year.
"But if the right opportunity comes along for the right player who will help the squad, the chairman is very positive about try to help the team achieve its goals this year."
Mowbray is busy studying Saturday's opponents Leeds United and will watch them again tonight at the take on Chelsea in the Capital One Cup quarter-final.
"It's historically been a difficult game for us," said Mowbray. "They have a tough game tonight so let's see if that takes it out of them."
Jason Steele suffered a trapped nerve in his ankle in the warm-up on Saturday but got through the game without problems.
"We called the doctor down to take a look at it. It settled down and fortunately he was able to play," said Mowbray.
Faris Haroun, who missed the win over Wolves with a calf injury, is expected to return to training this week.
Andy Halliday was due to have an injection in his Achilles to help clear up the problem that ruled him out at the weekend.