A lot will probably depend on who else is on the team and if they can afford to let him leave.
Right now, we know Locatelli and Fagioli are likely here. There's absolutely a scenario where Douglas Luiz signs, Rabiot leaves, and Koopmeiners is too expensive and we dont sign him.
If we're going into training camp with Luiz, Fagioli, and Locatelli as our starting midfield, with a cheap Koopmeiners alternative (like bringing back Alcaraz on loan) and players like Miretti, Nicolussi, Arthur, and Barrenechea competing for 1 or 2 spots, it may be tougher to let him go.
If Rabiot stays or Koopmeiners signs in addition to Luiz, we should have more than enough depth to be able to comfortable loan him out and rely on other players for depth.