Winger Nathaniel Mendez-Laing has joined Wednesday.
Mendez-Laing, who left Middlesbrough at the end of last season, has been training with the Owls in recent weeks.
The 29-year-old moved to Cardiff from Rochdale in 2017, helping them to promotion to the Premier League and playing 20 times in the top tier.
He then joined Middlesbrough in February of this year and, after leaving the Riverside in the summer, now becomes Darren Moore’s latest signing.