Earlier today, Reds owners Fenway Sports Group took the rare step of issuing a statement about the club's transfer policy, insisting that "no offers for Philippe will be considered" this summer.
The club have already turned down two approaches for the Brazilian from cash-rich Barcelona, who are in the market for a fast replacement for Neymar, including a most recent offer of £90m plus add-ons.
With Liverpool's stance clear and rumours of a new bid of more than £100m coming, Coutinho has reportedly submitted a formal transfer request in an attempt to push the move through.
Responding to the story, an unnamed family member told Sky Sports News: "Philippe has tried very hard to find an amicable solution to this situation but to no avail.
Coutinho will miss Liverpool's season opener at Watford this weekend and is a doubt for next week's Champions League playoff with Hoffenheim due to a back injury.