Parrott had initially been included in Mick McCarthy provisional Irish senior squad but subsequently took the step back down to the U21s.
Can made 37 appearances and scored four goals for Juventus last season under Massimiliano Allegri, whom Sarri replaced in the summer.
He signed his first professional contract with Spurs in February on his 17th birhday.
Thoughts on Juventus' excluding Emre Can from the Champions League group stage squad?
"I was extremely shocked yesterday because I was promised something else last week".
"Me and my advisor talked to other clubs [during the summer transfer window]". "Our conversation only lasted a minute and I wasn't given a reason". I can't explain it to myself.
The Italian champions have left Can and Mario Mandzukic out of their UCL roster for the 2019-20 season, as Maurizio Sarri has incredible strength in-depth in his squad.
"Now I draw my conclusions and will talk to the club and my agent".
Head coach Maurizio Sarri picked close-season signings Adrien Rabiot and Aaron Ramsey ahead of Can in his midfield ranks for the European games, with Juventus due to play Atletico Madrid, Bayer Leverkusen and Lokomotiv Moscow.
In an interview with German publication Bild, the German global says he stayed with Juventus under the condition that he'd get Champions League football.