The Premier League game on Sunday could help decide who finishes in the Champions League places this season.
The Brazilian has less than 10 Premier League appearances to his name this season, leaving him on course for his most disappointing season at Old Trafford since he made his debut.
But the dynamic fullback's game is tailor made to the wingback system Van Gaal is currently implementing, and the 24-year-old provided a reminder of his attacking ability on Tuesday in the Under-21s' 1-1 draw with Spurs.
It may have been a reserve match, but given that the two teams are right at the top of the Under-21 league, it was an intriguing affair, and one where the likes of Radamel Falcao and James Wilson were unable to make much of an impression against a solid Spurs side full of promising talent.
Rafael was impressive throughout, both in defence and going forward, and scored a superb lobbed goal from 30 yards out after goalkeeper Luke McGee's poor distribution.
In contrast, Antonio Valencia had a terrible game as United crashed of the FA Cup out to Arsenal on Monday. The Ecuadorian's woeful back pass to David de Gea gifted possession to Danny Welbeck for the winner, while it was down his flank that Nacho Monreal scored the opener. The former Wigan man struggled to influence the game from an attacking perspective too.
Van Gaal may well mix things up after the FA Cup exit, and surely Rafael would be an option to come in at a position that has been a problem for United this season.