J Pat Carter/Associated Press
At left wing-back, Luke Shaw begins his first United season with a hamstring injury, per BBC Sport, and is expected to be out a month. Assuming he makes a full recovery, he should quickly find himself first choice, unless a new signing arrives.
Competition for his place comes from Reece James, older than Shaw, but with far less top-level experience. Ashley Young's surprisingly excellent performances on tour mean he finds himself in the running to provide cover.
But for now, Shaw looks to have a fine opportunity to make the position his own, on his return to fitness.
On the right, much depends on whether reports of Rafael da Silva's impending departure, per Simon Jones and Sami Mokbel of Daily Mail online, have merit.
If they do, then it is clear that Van Gaal sees Antonio Valencia as his first-choice option, with Young providing back-up. Jesse Lingard has also played there this pre-season, although the position does not seem a good fit for his natural talents. He does not have the defensive experience required for the role.
Rafael has been retained the No. 2 shirt, per ManUtd.com, although it is probably a mistake to read too much into that.
If Valencia and Rafael are both at the club, then choosing a first-choice wing-back may depend on the opposition. Rafael offers enormous energy and defensive tenacity. His decision making leaves much to be desired, although that looked to have improved during the 2012-13 season when he was consistently impressive.
Last season saw the Brazilian regress, as many of United's players did. He also spent much of the season battling a series of injuries, something which may well worry Van Gaal.
Valencia offers enormous power and presence. He is defensively naive on occasions, unsurprising given his background as an out-and-out winger.
My guess is that Van Gaal considers the Ecuadorian first choice, but time will tell.