Manchester United boss Louis van Gaal has revealed defender Phil Jones missed Sunday's 1-1 Premier League draw with Chelsea due to shin splints.
England international Jones made his United comeback after four games out with a hamstring injury in the 2-2 draw at West Bromwich Albion on Monday.
But after the 22-year-old was absent again for the Old Trafford clash with Chelsea, Van Gaal gave an update on Jones' condition and said he did not know how long his latest setback would keep him sidelined for.
"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)."