Carver was the Magpies’ first-team head coach during the second half of the 2014-15 campaign following the departure of Alan Pardew to Premier League rivals Crystal Palace.
Under the Englishman, Newcastle almost got relegated to the Championship, and he was not kept in the job after the season finished.
Former Nottingham Forest and Derby County manager Steve McClaren is in charge of the Magpies now, but results are not improving.
Newcastle are second from bottom in the Premier League table at the moment and have yet to win a game in the league.
Former Newcastle midfielder Bowyer has defended Carver and has told talkSPORT: “It just shows you that the criticism John Carver was getting last year was unjustified. You can only work with the squad you’ve got.
“Steve McClaren has bought in some of his own players and one or two of them look ok, but to bring in foreign players again when you already had loads there - it’s a tough league to hit running and not a lot of players get it.”
Bowyer’s comments about Carver are debatable, as the Englishman inherited a squad that was doing relatively well.
When Pardew left Newcastle, the team were 10th in the Premier League table and were pretty much guaranteed mid-table security.
The least Carver could have done was to keep the Magpies around mid-table, but under him the team almost went down to the Championship.