The 26-year-old is enjoying a very good season for club and country so far.
While Kelleher did commit an error in a 3-3 draw with Newcastle United, he has been stellar otherwise.
The shot-stopper is expected to drop out of the team when no.1 Alisson Becker is fully fit and match sharp.
Speaking on Premier Sports Ireland, O'Shea said of Kelleher: "He's going to have lots of teams all around Europe looking for him and I'm sure they'll be knocking down the doors very soon.
"I know for a fact there will be lots more teams looking at him because I just think he's a number one, top European goalkeeper."
- Get breaking football news faster with the new Tribal Football app! Download now on iOS and Android to stay ahead of all the latest transfers and football updates. Download now: App Store, Google Play