After joining from Rayo Vallecano, the Spaniard enjoyed a stellar first Premier League campaign in 2012-13, scoring 18 times in 35 appearances.
He struggled with injuries during 2013-14, netting just twice in 17 outings, and was allowed to go out on a season-long loan to the Serie A club at the start of the campaign.
The 28-year-old has made just three league appearances under Rafael Benitez as he continues to struggle with his fitness, sparking rumours that he could make an early return to Wales.
But in a press conference on Thursday, Monk moved to quash such talk.
"Nothing's changed as far as I'm concerned," he said. "I know he's struggling with his injury, but communication between the club is nothing about him coming back.
"I will focus on players here. Michu made the decision to try a different challenge which I supported because we have a great relationship.
"But in terms of this season I'm dealing with the players we have here."
