Jones missed yesterday's 1-1 draw with Chelsea.
"The match against West Brom was his first after a long injury period," Van Gaal said.
"We brought him back and he trained for more than a week with the first team, then had to play 90 minutes.
"Then he had a sore feeling in his shin. On Saturday he could not continue training, even though it was a very light session before the match.
"He had shin splints, which is very painful. I don't know how long it will take (for him to recover)."
For the big stories and the banter follow us on Twitter: @tribalfootball