Defoe could still move before the month is up, but his manager is blocking any possibility of such a transfer.
Defoe was linked to Nottingham Forest on loan, but Howe believes he still has a vital role to play at the Premier League side.
When asked by Sky Sports about Defoe possibly leaving, Howe replied: "No I'm not going to let anyone go, our squad is our squad. We're not huge on numbers, and we also have a couple of injuries at the moment.
"Jermain's a valued member of our squad, we only carry four strikers so there's absolutely no chance of him going anywhere."