Pompey have extended the loans deals of Scott Allan and Jake Jervis.
Both players will remain with the Blues until Friday, January 4 – including the League One match at Walsall.
Allan arrived from West Brom in October, having spent part of last season on loan at Fratton Park.
The midfielder has made six Blues appearances this term, scoring once.
Striker Jervis was signed from Birmingham last month and has played three times for Guy Whittingham’s side – scoring in the 2-2 at Tranmere.