The 24-year-old made just two appearances for the Championship side in January.
The New Zealander - who is the club's top goalscorer in the Championship this season with eight goals - was initially sent for a first scan after limping off during the early stages of the Whites' 1-1 draw with Brentford, nearly a month after suffering a similar end to his game when Steve Evans' men faced Derby County in December.
However, the Yorkshire Evening Post reports that the original scan came back inconclusive, leaving United to wait in hope that this latest attempt will provide clarification.
Although Evans still has Souleymane Doukara and Mirco Antenucci available to him - despite speculation linking the latter with a return to Italy during the January transfer window (via Yorkshire Evening Post) - he would have certainly been hoping to have had the former Leicester man back in the squad, or at least have an understanding of when he will be back in training.
With a game against automatic promotion chasers Middlesbrough following Saturday's clash with Nottingham Forest, Evans will know that, despite Doukara's excellent recent form - the 24-year-old has scored four goals in his last six games in all competitions - they may have stood a better chance of getting their play-off push back on track if they had Wood available.