The Italian arrived at the Stadium of Light at the start of the current campaign and has made 18 appearances in his debut season, but he was not even in the matchday squad last weekend.
Head coach Poyet confirmed the 28-year-old was not injured, but remains adamant he will play a crucial role in helping Sunderland secure Premier League safety, particularly after Steven Fletcher suffered an ankle injury against Palace.
"People will ask why Giaccherini wasn’t even on the bench; he's an Italian international and I know, it hurts," Poyet told the Northern Echo.
"I need him. Maybe he doesn't believe me, but I need him, because now if Fletch (Steven Fletcher) is not available then maybe we will need Giacchi there.
"And then he needs to help us, and I'm sure he will because he's a great professional.
"He will be sad because he will probably think it was an opportunity lost for him, but we will need everybody."
Fletcher is expected to miss a large part of Sunderland's run-in and his anticipated absence could lead to Giaccherini featuring at Norwich City this weekend.
