The 29-year-old, who has struggled with a multitude of fitness issues over his Reds career, was forced off the pitch and replaced by Rhys Williams just before the hour mark.
Matip pulled up after an attempted clearance and immediately signalled to the bench to come off.
Speaking in his post-match press conference after Sunday’s match at Anfield, Klopp confirmed the centre-back went off with an adductor injury.
‘Joel has told me he felt something in his adductor which is obviously not too good,’ the German boss said.
‘I’m not sure how serious it is right now but he had to come off. We will probably get more information tomorrow.’
Klopp also added that midfielder Naby Keita missed the West Brom clash with an unspecified muscle injury and will sit out Wednesday’s trip to Newcastle.
‘He has a muscle injury,’ he said. ‘Don’t know exactly how long. Not today or Wednesday so we will see.’
Liverpool have already lost Virgil van Dijk and Joe Gomez to serious knee injuries this season and had to rely on Fabinho, who is naturally a midfielder, filling in.
Klopp may have to call on inexperienced youngsters Williams and Nat Phillips again for cover after Matip’s latest injury issue.
Sadio Mane opened the scoring after 12 minutes, with Matip firing in a cross for the Senegal international to emphatically finish.
Klopp’s side dominated for large periods but had just two shots on target over the 90 minutes.
West Brom improved after the break and punished their opponents with a late header from Semi Ajayi which earned Sam Allardyce his first point since being appointed West Brom boss earlier this month.