Belgian midfielder Julien De Sart has left Middlesbrough on loan until the end of the season.

The 22-year-old, who signed for Boro 12 months ago from Belgian club Standard Liège, has agreed to join Championship side Derby County after barely featuring at the Riverside.

De Sart has made just three appearances for Aitor Karanka’s side after signing a three-and-a-half-year deal in January last year.

Boro have plenty of options in midfield

His only start came in Boro’s Capital One Cup defeat to Fulham back in August and the Belgian has more recently appeared for Paul Jenkins’ Under-23s side.

Boro will still hope that De Sart can develop into a first-team player in the Premier League. However, with Adam Forshaw, Adam Clayton, Marten De Roon and Grant Leadbitter all offering more top-flight experience, Karanka isn’t short of centre midfielders.

McClaren is a fan of the young midfielder

De Sart will hope to break into a Derby side which have picked up under former Boro manager Steve McClaren and moved up to seventh in the table following a dismal start to the campaign.

"He is a talented player with plenty of potential," said McClaren after the deal was completed.

The midfielder will be available for Derby’s game away at West Brom in the third-round of the FA Cup on Saturday.

De Sart isn’t the only player who has been allowed to leave the Riverside today.

Boro have confirmed that backup goalkeeper Tomas Mejias will also leave on loan.

The 27-year-old has joined the Spanish second division side Rayo Vallecano until the end of the campaign.

Soisalo follows Gestede to join Under 23s

Meanwhile, the Teessiders have completed their second signing of the January transfer window, following the £6 million arrival of striker Rudy Gestede yesterday.

Finnish forward Mikael Soisalo has signed for the club from Finnish top tier side Ilves Tampere.

The 18-year-old, who scored seven goals and provided six assists for Tampere last season, will train with Boro’s Under-23 side.