Arne Slot explained why Joe Gomez needed to be substituted 10 minutes into Liverpool's Emirates FA Cup tie at Plymouth Argyle on Sunday.
The defender was named in the starting line-up and wore the captain's armband at Home Park, featuring for the first time since December 29 following a hamstring issue.
However, Gomez felt some discomfort during the opening exchanges of the contest and was subsequently replaced by Isaac Mabaya.
Asked for an update on the No.2's condition, Slot told his post-match press conference: "I am not too sure. I am not too sure if it was the same leg, but I haven't had time to ask him. It was clear, I think we all know which moment he felt a bit insecure about [it] because he didn't sprint back fully.
"Then he said, 'I am not 100 per cent sure and I am afraid if I make one extra sprint things will go wrong.'
"It's not torn I assume, but it didn't feel good for him. That was a bit of a blow because Curtis Jones was on the bench, but he came to me this morning and said, 'I don't think I am fully recovered yet' as well after the training session of yesterday.
"That all of a sudden led to the fact we were with a few more youngsters on the pitch than was the idea before the game, but still there was enough quality on the pitch to get a better result than this."