The Swansea boss was very disappointed in the midfielder after his sending off against Everton.
"His commitment isn’t in question but sometimes his judgment is," Monk told reporters. "You have to be clever - you play with intensity but a cool head. It’s the first one, the sloppy ones, we can cut out.
"He has to learn very quickly. He’s got a few weeks to think about it."
But will Shelvey ever learn?
The Swans midfielder is now 22 - yet nothing has changed since he burst onto the scene as a teenager.
And that's exactly why Liverpool offloaded him to Swansea.
Make no mistake, Shelvey's talent is not in question. His form for Monk's side has shown as much. His passing and movement is extremely promising, while some of the goals he scores are up there with the best in the Premier League.
Shelvey, however, is just too prone to rushes of blood to the head. He lacks composure. And the way the young midfielder is, that doesn't appear to be something that can just be removed from his game at will.
If there was any doubt, then, that the Reds were wrong to sell him, there should be none anymore, no matter how bad their midfield struggles may be.
For Monk, meanwhile, the frustration with the former Liverpool man will likely continue. But it will be countered by the fact that the 22-year-old, on form, is capable of producing moments of absolute magic. It is certainly a trade-off.