Mudahim, one of Jenny Pitman's two remaining entries in the Welsh National, is rated as having only a 60-40 chance of lining up on December 27th.
The 11-year-old, unraced since capturing the Irish Grand National last Easter, has 11 st 1 lb in the Chepstow marathon but Pitman's husband and assistant David Stait conceded: "It would be touch and go whether he's ready as he didn't come back to us until late.
"It's probably 60-40 against running at the moment. Obviously we'd like to get him there but if we feel he's short then he won't run."
Pitman had withdrawn Nahthen Lad from the three mile five furlong contest leaving Jet Rules, whose return to action saw him beaten 53 lengths into sixth behind Sesame Seed at the Welsh track last Saturday, as the only other possible.
A decision on Jet Rules' participation will be made in the next few days said Stait.