Jeremy Toljan made his Celtic debut on Sunday after completing a deadline day loan move from Borussia Dortmund.
Toljan was named on the bench for Celtic’s trip to St Johnstone but was forced into action when Mikael Lustig could not continue for the second half.
Lustig felt his Achilles and it got progressively worse in the first half of the Scottish Premiership match, BBC Sport reports.
It is unclear at the moment whether Lustig will face a spell on the sidelines but with a game coming up on Wednesday, Brendan Rodgers will probably not risk him.
This could hand Toljan a glorious opporunity – albeit in unfortunate circumstances – to stake his claim for a regular starting spot.

The starting right-back spot is definitely up for grabs as Lustig struggles for his form. And with his contract coming to an end, the 32-year-old’s future is up in the air.
Rodgers is yet to make a decision on whether to offer the Sweden international fresh terms, but Toljan could help make up his mind.
The 24-year-old is only on loan from Borussia Dortmund but with game time looking limited in Germany, he might be forced into a permanent exit in the summer.
If he can impress Rodgers, Toljan might earn himself a permanent contract at Celtic, which could end Lustig’s hopes of staying beyond this season.
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