Rakitic has fallen out of favour with Barcelona manager Ernesto Valverde this season.
The 31-year-old has featured in eight games out of twelve so far, but only for a combined 203 minutes.
With the acquisition of Frenkie De Jong from Ajax last summer, and the continued preference of Arthur, Rakitic's chances in midfield are more and more limited.
There are now seven midfielders in the Barcelona squad and it's thought Rakitic could be followed out of the club by Arturo Vidal and Carles Alena.
The Croatian was reportedly the subject of numerous bids from across Europe last summer but was reluctant to entertain them as he was happy in Spain.
United coach Ole Gunnar Solakjaer recently said the club might be looking to add experience to a relatively young squad.
“There might be some experienced players who can come in and help the younger players – that might be worth the money."
Meanwhile, Maurizio Sarri is rumoured to be keen to add another body in midfield to ensure Juventus are able to cope across all domestic and European competition.
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