Head coach Nuno Espirito Santo has made it clear neither player features in his plans for the future and, with Wolves keen to get the pair off the wage bill, both permanent and loan offers are being entertained.
The Express & Star claim a number of Championship clubs have expressed an interest in Marshall, 26.
The former Blackburn Rovers and Leicester City wideman has not made an appearance in the league since November 3.
Zyro hasn’t featured since an outing in the EFL Cup on September 19 and both English and European teams are said to be keen on his signature.
Rangers defender David Bates faces at least six weeks out with ankle ligament damage.