Gretna will play their next two 'home' SPL matches at Livingston's Almondvale Stadium, following drainage problems with the Fir Park pitch.
Several games have been postponed at Motherwell's home, which has been shared by Gretna this season.
Gretna, currently in administration, entertain Celtic at Almondvale on Sunday and Inverness on 5 April.
Motherwell visit Dundee United on Saturday and no decision has been made about their next home fixture.
"Talks are ongoing in relation to the Motherwell v Hibernian fixture on 29 March, with a range of options being explored," said SPL executive chairman Lex Gold.
The postponement of Saturday's Motherwell v Celtic game added to the fixture pile-up facing the SPL, with five matches still unscheduled ahead of the league split on 5 April.
And Gold added: "This is the most difficult and unprecedented fixture situation that we have faced.
"Our priority over the past weekend has been to confirm the arrangements for Gretna's match against Celtic.
"We thank Livingston and other clubs with whom we have been in discussion for their assistance.
"The remaining Gretna home game against St Mirren will be allocated in the coming days.
"Further developments in relation to Motherwell's other home games will depend on the work currently being done to assess when Fir Park will available again for SPL matches."
On Saturday, Motherwell chairman John Boyle apologised to fans after the latest postponement.
And he asked the SPL to consider switching games away from Fir Park in a bid to help the pitch recover.
He added that everyone at the club was "hugely embarrassed" and that he had arrived at the "expensive conclusion" that the whole surface would have to be ripped up.
Motherwell are considering their options until the end of the season with a home match being played away from Fir Park still a possibility.
A club spokesman said: "We are going through a decision-making process that we have got to get right.
"The fact we have to get it right means we are going through all available possibilities."
Celtic's chief executive Peter Lawwell had offered to host Sunday's match at Celtic Park but added they would be happy to play at any SPL approved ground.
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Gretna are in a perilous financial situation and will be hoping for a sell-out crowd against Celtic.
The ailing club needed to draft in U19 players to make up their travelling party to Aberdeen at the weekend.
With players owed wages, several first team regulars refused to participate.
But a Gretna spokesman said: "Next week's game is not in question and it will go ahead, that's the impression we have got from the administrators.
"It is after that game that it becomes more worrying because we only have one more home game before the league splits in two.
"We have to play it by ear and deal with everything on a daily basis."
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