Phil Jones is battling to be fit for Manchester United's hectic April fixture schedule after suffering a suspected broken toe on England duty while being tackled in training.
Jones, 25, was sent back to his club by England manager Gareth Southgate on Tuesday for X-rays after being injured in training prior to the national team's departure for Germany ahead of Wednesday's friendly against the world champions in Dortmund.
With United due to play nine games next month, including the Europa League quarterfinal doubleheader against Anderlecht and a local derby against Manchester City on April 27, the potential loss of Jones will be regarded as a major blow by manager Jose Mourinho.
Southgate will consider whether to replace Jones in his squad after the Germany game -- Chelsea defender Gary Cahill is suspended for Sunday's Wembley World Cup qualifier against Lithuania -- but he admitted that Jones was unable to be considered for either the Germany game or the Lithuania clash.
"We don't know the full extent of it," Southgate said. "We didn't feel it was an injury that Phil would be able to train or play with.
"We have respectfully sent him back to his club and we will know more once he has had scans and an X-ray over the next 24 to 48 hours."
Despite suggestions that Jones was injured in a challenge with United teammate Chris Smalling, Southgate was unable to specify the exact cause of the injury.
"It was just an innocuous tackle," he said. "Phil caught the bottom of his foot in the challenge and we think he suffered an injury to his toe."
Southgate, meanwhile, confirmed that Raheem Sterling is a doubt for the Germany game after the Manchester City winger missed training on Tuesday following his exertions in Sunday's Premier League encounter with Liverpool at the Etihad Stadium.