The 23-year-old defender is in the final year of his contract at the Madejski Stadium, and could be available at a knockdown price in January, as the Royals risk losing him on a free transfer next summer.
Reds boss Brendan Rodgers has been credited with an interest in Pearce, despite the fact he has made only four Premier League appearances this season, following the emergence of highly-rated youngster Sean Morrison.
Despite that, McDermott is keen to keep the Republic of Ireland international at Reading, and hopes that negotiations with Pearce can be ironed out ahead of the New Year.
"I want him to sign and he has to make a decision, but January is coming," he told the Daily Star. "If the two parties can't agree a deal, then what can you do?
"I never get involved in the money side of things. But it's not a case of take it or leave it."
Liverpool's current first-choice centre-back pairing consists of Daniel Agger and Martin Skrtel, with Sebastian Coates and Jamie Carragher in reserve.
But, with Anfield's most capped player entering the twilight of his career, Rodgers is already looking to find a future successor, and is ready to make a cut-price offer for Pearce in the forthcoming window.