Anderson, who came through Newcastle United's academy and had been a growing presence in the first team, was sold for £35million as part of the club's effort to comply with Premier League Profitability and Sustainability Rules. He scored a 73rd-minute equaliser on Sunday in Nottingham Forest's 1-1 draw at St James' Park — a headed finish from a corner — adding another chapter to what has been a breakout top-flight season.
Howe addressed the subject with characteristic directness in his post-match press conference.
"It was something we regretted when we were doing it. We knew that would be a very, very painful transfer, one that we had to do. We had no choice — but it was probably the most reluctant transfer I'll ever do, because we knew the quality of the player."
He recalled the impression Anderson had made before his departure.
"We'd seen him close up for a number of years training with us. He was beginning to break into the team and he was being, for me, the back end of that season, really effective in a number of different positions."
Sunday's goal clearly stung.
"It really hurts to see him do that against us today. He's going to go and have a fantastic career, wherever he goes, wherever his career takes him. He's a great lad as well, so it's painful for us to take — but he's an outstanding player."
Anderson has made 31 Premier League appearances for Forest this season, scoring three goals and providing four assists from central midfield. At 22, he is the kind of player Newcastle spent years developing and would have built their midfield around. The PSR rules that forced the sale have since been the subject of significant criticism from multiple Premier League clubs.
The equaliser at St James' Park cost Newcastle two points in their survival fight. They remain one point above the drop zone with two matches remaining.