Hibernian ran out of time to complete a last-minute deal for St Mirren midfielder Jamie McGrath, but Middlesbrough defender Nathan Wood has joined on a season-long loan.
McGrath, 24, was linked with a move away all summer, with St Mirren turning down multiple offers for the Irishman.
Hibs made a late bid but could not conclude an agreement before the midnight deadline on Wednesday.
But the Edinburgh club have also signed goalkeeper David Mitchell from Clyde.
Former Dundee keeper Mitchell, 31, joins Hibs as back-up to Matt Macey on a two-year deal.
Meanwhile Wood, 19, became Boro's youngest ever player when he debuted at 16 years and 72 days in 2018 and was loaned to Crewe Alexandra last season.