He had a 4 yr contract and wanted a new challenge. Maybe if he was 30+ he would have signed a new deal. His agent has manage to find him a PL club, which will also help his international career. I'm sure he spoke about his options with Irish management team.

How many players in last 5 years have been here longer than 4 years (as a full time professional)?
Woody
Smith
Mattock

How many players have we given 5yr deals too?

If we had sold him last yr as a L1 player with a yr left, £700k at best.

If we sold him 2 yrs ago as a relegated championship player, then similar to Crookes or Ajayi, maybe £1.2 to £1.5m, if those offers came in we would have sold him, but they didn't as clubs not wanting to pay that much for a RWB from Rotherham.

If selling now his worth increased due to breaking into Ireland squad and them playing him as a forward. We then struggled to sign a decent forward so played him up front. If Warne had signed a decent striker or two at start of last season, Cheio would still be played at RWB. Most likely he would have left at end of his contract any way to find a club that would play him as a forward and a new challenge.

All ifs and buts for a winger plenty moaned that couldn't cross and wanted shut in Jan transfer when his effort and contribution waned.