Oxford will leave it late before deciding whether or not Harry Worley and Michael Duberry are fit.
Defender Worley picked up an ankle injury in the 2-0 win at Accrington in midweek, while experienced centre-back Duberry has a groin problem which has kept him out of Oxford's last two outings, and the club's medical staff will assess the pair on Saturday prior to kick-off.
Otherwise, manager Chris Wilder has no other new injury or suspension worries, but he will continue to be without a handful of first-teamers.
Jon-Paul Pittman continues his recovery from a hamstring problem, Tony Capaldi is close to a comeback after a knee complaint and Tom Craddock (knee) is also on the mend, but none of the trio will take part against the Shrimps.
Alfie Potter is out for the season with a broken ankle.
Morecambe boss Jim Bentley expects to have Jack Redshaw and Gary McDonald available.
Forward Redshaw and midfielder McDonald were both absent from last weekend's home defeat to Shrewsbury with minor hamstring strains.
On-loan Carlisle man Craig Curran could be in line for a full Shrimps debut after featuring for the reserves against Manchester City in midweek.
Experienced defender Nick Fenton returned after a month on the sidelines with a calf injury against the Shrews and is set to continue, having suffered no reaction to the problem.
Top scorer Kevin Ellison is expected to win his seemingly weekly battle with a persistent back complaint, while Laurence Wilson and Andy Fleming (both knee) are out for the rest of the season.
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