The 25-year-old Sweden international has emerged as a target for Premier League champions Liverpool, who are exploring options to strengthen their forward line. Sources told ESPN earlier this week that Isak is under serious consideration as part of Liverpool's search for a new number nine.
Despite the mounting interest, Howe insisted post-match that he remains confident Isak will still be at St. James' Park when the transfer window closes on September 1.
"It was my decision," Howe said. "He travelled back to Glasgow with us but I decided to send him home due to the speculation around him. The last thing he wanted was to be sat in the stands watching. That wasn't fair to him."
Isak's omission comes at a time when Newcastle are preparing for a return to Champions League football, having qualified for Europe's top competition in two of the past three seasons. Losing their top scorer - who netted 21 goals in all competitions last term - would be a significant blow, but Howe suggested the club is not preparing for life without him.
"I'm confident he will be a Newcastle player come the end of the window," Howe said.
The Newcastle boss also revealed he's spoken to Isak directly about his future, and praised the striker for maintaining a professional approach amid the ongoing rumours.
"Yes, I've had discussions with him, but that's not abnormal," Howe added. "I respect a player's career and how short it is. Alex has been really good - he's trained well, and I realise there'll be noise around him."
Isak joined Newcastle from Real Sociedad in 2022 for a club-record fee and quickly established himself as one of the Premier League's most effective forwards. His ability to play across the front line has made him an attractive target for top clubs across Europe, but Newcastle remain hopeful of fending off interest as they look to build on a season that saw them finish fifth in the league.
With just over a month remaining in the transfer window, Isak's future remains a key storyline at St. James' Park - but for now, Eddie Howe appears determined to keep his star striker focused on the season ahead.
Arne Slot has admitted that Liverpool "need to do better" at bringing Alexander Isak into dangerous areas after another quiet outing for the Swedish forward in Wednesday's 1-1 draw with Sunderland.
Tottenham snatched a dramatic 2-2 draw at St James' Park as Cristian Romero produced a 95th-minute overhead kick to rescue a point against Newcastle.
Newcastle United have received an unexpected boost after Yoane Wissa was omitted from the DR Congo squad for the upcoming Africa Cup of Nations, which begins on 21 December.
Alexander Isak said he felt "real relief" after finally ending his Premier League goal drought for Liverpool, guiding Arne Slot's struggling side to a much-needed 2-0 win at West Ham.
