Liverpool have announced that Joel Matip will leave the club's pre-season tour of the United States to undergo treatment on a thigh problem.

Matip missed the closing stages of last season after suffering an injury to the same area, but the centre-back had returned to action during Liverpool's early friendlies ahead of the new campaign.

However, the 26-year-old sustained a similar problem during Sunday's 3-1 defeat to Borussia Dortmund, and the Merseyside giants have confirmed that the Cameroon international faces another spell on the sidelines.

A club statement read: "Joel Matip will leave Liverpool's pre-season tour of the United States to undergo rehabilitation on the muscle injury he sustained against Borussia Dortmund on Sunday.

"The defender picked up the issue midway through the first half of the International Champions Cup fixture and was immediately substituted.

"Though the muscle injury suffered in his upper leg is not considered to be a long-term concern, Matip will not be available for selection in the remaining two games in America."

Liverpool begin the top-flight campaign with a home fixture against West Ham United on August 12.