For Eddie Howe, being back on Newcastle United’s training pitches in Benton will have been cathartic.Victor Munoz has already joined Liverpool, Johan Manzambi is Aston Villa-bound and, although three exciting youngsters have been acquired, the Newcastle first XI currently appears depleted following the sales of Anthony Gordon and Sandro Tonali for up to a combined, and impressive, £170million ($229.5m), while uncertainty lingers over Bruno Guimaraes’ future, given Arsenal’s seemingly indirect interest in Howe’s captain.On Monday, those Newcastle players who did not represent their nations at the World Cup returned to the renamed “The KNOX” — the sports-drink company is paying £6million per season to be the club’s first-ever training-ground sponsor — and underwent testing, before taking part in some rigorous sessions.That core group numbered around a dozen. Sean Steur and Ewen Jaouen, the club’s new midfielder and goalkeeper, have trained, while Bazoumana Toure, the winger signed from Hoffenheim, will join up with his new team-mates later this month.England’s Dan Burn is still in the United States ahead of Saturday’s third-place play-off against France, while Brazilian Guimaraes, DR Congo’s Yoane Wissa and Anthony Elanga of Sweden, as well as Germany duo Nick Woltemade and Malick Thiaw, will filter back to Tyneside at varying intervals, with all players afforded at least three weeks off after the end of their country’s World Cup adventure.Although there has been the positive sight of Lewis Miley running on the grass after a broken leg, the 20-year-old midfielder is unlikely to feature until deeper into pre-season, and the same is true for Tino Livramento, the 23-year-old right-back who pulled out of the England squad shortly before the World Cup began to have a calf operation. The hope is that both will be fit for the opening Premier League match at home against Liverpool on Sunday, August 23.Lewis Miley is back running on grass, but is unlikely to feature until later in Newcastle’s pre-season (Stu Forster/Getty Images)To bolster numbers, as is usually the case early during pre-season, Howe has invited a host of Robbie Stockdale’s under-21s squad to join the senior sessions. More are expected to be given first-team opportunities in the coming weeks, too.Newcastle’s under-18s are currently in Marcoussis, near Paris, for a training camp. Sam Alabi, a midfielder who was named in four senior squads last season, including the Champions League trip to Marseille, and fellow 17-year-old Isaac Moran, a defender who has trained with the first team on occasion, are both on that trip, but may feature when they return. Mason Miley, also 17, a midfielder who is the younger brother of Lewis and signed his first professional contract this week, has been at the academy, training with Stockdale’s side, yet may come into consideration.The youth ranks are being bolstered, too, with sporting director Ross Wilson keen to keep boosting the quality at the academy.Johan Martinez, an Ecuadorian winger, will only join from Independiente del Valle once he turns 18 next May, but multiple domestic signings are also in the works. Kyran Thompson, a much-coveted 16-year-old attacker, is set to arrive from Arsenal, while right-back Kyle Healy-Matthews, also 16, is expected to move from West Ham United.For now, though, with Joe White having left permanently for League Two outfit Crewe Alexandra after a decade on Tyneside, and Harrison Ashby spending the coming campaign on loan at League One side Luton Town, less experienced members of the academy setup are in line for first-team opportunities.