Kagawa re-signed for Dortmund from Manchester United before the transfer window closed, and the playmaker enjoyed a dream return as he scored in Saturday's 3-1 Bundesliga win over Freiburg.
Klopp himself revelled in seeing Kagawa back in Dortmund colours but an injury list headed by attacking star Marco Reus means he will proceed cautiously with the Japan international ahead of the Group D opener.
"For a first game back it was an extraordinary one for him on Saturday," Klopp told Monday's pre-match press conference. "We saw the opportunity and used it to bring him back and at least here everyone is happy."
"A decision whether he will play tomorrow will be taken tomorrow morning."
One man on the mend for Dortmund is Sven Bender, with the defensive midfielder in contention to replace Milos Jojic having missed Germany's FIFA World Cup triumph with a thigh injury.
"Sven Bender is an option for tomorrow," Klopp stated.
Arsenal are a familiar foe for Dortmund at this level, having been drawn in the same group as the Premier League outfit in 2011 and '13.
Arsene Wenger's team are famed for their free-flowing attacking style, but Klopp acknowledged the London outfit showed another string to their bow in a 1-0 win at Signal Iduna Park in November.
"Those who saw Arsenal here last year know very well they can also play defensive football and switch their game very quickly," he added.
