However, Pottinger has refused to name the club that made the bid for the highly-rated 21-year-old, who has featured for Wales Under-21s.
He wrote on Twitter: "Today the Board turned down a bid of £400,000 for Joe Walsh. The offer is way under his valuation. Joe Walsh is a big part of our plans."
Walsh, who moved to Crawley from Swansea City in 2012, is regarded as one of the brightest defenders in the Football League.