Stories in the British press on Monday said a Middle East consortium was close to an £80million takeover of the Royals, but Madejski moved quickly to dispel the claims.
"To suggest that the club is close to being sold is simply inaccurate," he said.
"I have never made any secret of the fact I would like to sell if somebody with deep pockets was to come along and it was right for the club."
Watford have signed the Manchester United defender Craig Cathcart on loan until January.
Cathcart, 20, will join fellow Old Trafford loanee Tom Cleverley at Vicarage Road.
The central defender has previous Championship experience after making 33 appearances for Plymouth Argyle last season.
Barnsley are waiting for the results of a second scan to discover the extent of the injury to midfielder Jamal Campbell-Ryce.
He was forced to leave the field during Saturday's match with Watford after being hit in the face by the ball.
An initial scan showed that Campbell-Ryce had not suffered a detached retina, a second test was due to be carried out on Monday to allay further fears of any serious damage.
The Middlesbrough chief executive Keith Lamb has confirmed that England U21 winger Adam Johnson is to be offered a new contract at the Riverside Stadium.
Johnson, who scored both goals in Boro's 2-0 win at Scunthorpe earlier in the season, is out of contract in the summer.