Steve Bruce admits Callum Wilson should have been taken off during the 4-2 win over Leicester City.
The 12-goal top scorer has suffered hamstring issues since the victory against the Foxes and has been ruled out fo the final three games of the campaign.
But Bruce feels that Wilson may have been able to play a part had Newcastle acted earlier from the bench.
He said: "In hindsight, I should have taken him (Wilson) off before but it's his other side to his previous injury.
"We expect it to be two or three weeks so it's nothing like the last one which is good news.
"But still a shame he can't finish the season with us."
However, Newcastle have no fresh injury woes going into the encounter with the newly crowned champions Manchester City.
Bruce said: "Thankfully there's nothing to report. Let's hope its stays that way for the next week or so and let everybody have a well-deserved break."
Bruce announced yesterday that he expects to be here next term and will oversee pre-season.
The Magpies announced two pre-season friendlies yesterday, with games against York City and Harrogate Town both to be played on July 18. The rest of the schedule is yet to be confirmed.
