Bolton's attempt to lure James Morrison to The Reebok Stadium has been quashed after Albion immediately turned down their offer - believed to have been in the region of £3 million.
The Scotland international has made 18 appearances so far this season for the Baggies scoring twice against West Ham and Aston Villa and played an integral part last season in helping Albion win their first title for 88 years.
"It's always a positive when other teams want your players," Tony Mowbray said.
"It shows they're doing something well.
"But I don't see any reason why we would want to sell our better players.
"We're in a situation where we've got to stick together and work extremely hard to get enough points to ensure we can build again on the current squad next season and try to improve the club - not sell our best players.
"Has there been any more contact from Bolton?
"No - and James is not for sale.
"I'm always disappointed when any conversations between clubs come out in the press because it can disrupt footballers.
"Not that it will James because he's a diamond of a lad.
"He knows he's in the right place to develop his career.
"If his career ever moves on from West Bromwich Albion, it will be at the right time for both his career and our club.
"That moment is not now."
Morrison is set to miss tomorrow's game in the FA Cup against Peterborough with a tight groin with Mowbray sure any speculation will not hinder the 22-year-old midfielder.
"James is fine," Mowbray continued who also admitted his disappointment at the offer being reported to the media.
"As players do in dressing rooms, he's been taking a bit of banter from his team-mates. It's as light-hearted as that.
"With the utmost respect to the club who have made contact, I don't think it's something that would appeal to him.
"It's dead as far as I'm concerned and dead as far as James is concerned.
"He's done his job for the team this season.
"He's a young man who we ask to play different positions and, whatever we ask him to do, he's gives us everything he's got every week."