Sky Sports are reporting that
The 27-year-old winger has only featured in five Premier League games this term and is now expected to spend the rest of the season at the Riverside Stadium.
With the move set to go through as soon as possible, he will likely be available for Middlesbrough's Championship visit to sixth-placed Derby on New Year's Day.
Tony Pulis' side are currently fifth after 24 games and seem intent on chasing promotion to the Premier League following last season's relegation from the top division.
To help his side's promotion bid, the Boro boss is desperate to add a pacy winger to his side; still feeling the absence of Adama Traore, who left for Wolves in the summer.
Van La Parra - who incidentally is the half-brother of Liverpool midfielder Gini Wijnaldum - was a first team regular for David Wagner's side during their debut Premier League campaign last season but seems to have fallen out of his current manager's plans, currently looking to be surplus to requirements at the club.
Perhaps the Dutchman will rekindle his season if he is to make the drop to Championship this January - he just has to pass that medical.
Source : 90min