Brendan Rodgers has admitted a few Celtic players are carrying injury "niggles" as he was quizzed on Alistair Johnston's fitness.
The right-back was not involved in training with his team-mates on Friday ahead of the Premier Sports Cup tie against Falkirk on Sunday.
Cameron Carter-Vickers was another notable absentee ahead of this weekend's Scottish League Cup action.
Rodgers has now explained that training was split into sections in a second recovery day for Celtic players after the Champions League win over Slovan Bratislava.
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While a large number of key players were out training at Lennoxtown, another group took part in recovery sessions with "one or two" inside for recovery rather than out on the grass.
Pressed on Johnston's condition ahead of the match against Falkirk, Rodgers said: "We've got a few players with niggles so we will have a look at that and assess that by end of play tomorrow. We won't take any risks with one or two.
"It was the second day of recovery as well so there was a group of the players out recovering and a group training hard and then one or two inside just making extra recovery inside rather than out."
