I think he has suffered from injuries in the last couple of years and he is still 23 , turning 24 this year so he is hardly someone whose time has come and gone.In fairness Sean Twomey has done little to show he’s ready to start in Championship. He didn’t play one minute of Championship last year.
I remember he did well against Galway in the league last season, then got injured and never got going again for Cork.
I don't read too much into Co-op league games but against Clare he certainly was working very hard and of course physically he is a threat.
I think he will get chances in the league to show if he is up to this level now.