Hourihane completed his much-anticipated move to Aston Villa on Thursday, adding to the exits of Sam Winnall and James Bree from Oakwell earlier this window.
Despite playing more 20 times this season for Leeds, Mowatt has had a peripheral role since Garry Monk at the start of the season.
The midfielder has little over six months left on his contract and discussions with Leeds have so far failed to lead to an extension of that deal.
The 22-year-old, who won Leeds’ player of the year award in 2014-15, would be available on a free transfer in July and the Whites may look to cash in should a bid be put in front of them.
Sources close to Mowatt said that Barnsley had been prepared to delay their move until the summer with a view to tying him to a three-year deal.
But following the recent exodus of players, boss Paul Heckingbottom wants immediate recruits to sustain their form in the Championship.