Leeds United hope to recall Luciano Becchio for the clash with Portsmouth, but Andy O'Brien is set to miss the Championship game at Fratton Park.
Becchio appears to be winning his fight against the back injury which ruled him out of Wednesday's FA Cup replay against Arsenal, but a hamstring strain looks likely to prevent defender O'Brien from featuring on the south coast.
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United's experienced centre-back limped out of the 3-1 defeat to the Gunners midway through the second half, and the brief interlude between Wednesday's tie and this weekend's visit to Portsmouth left little time for O'Brien to recover.
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Manager Simon Grayson turned to Leigh Bromby to replace him for the final 24 minutes on Wednesday, and either Bromby or Neill Collins will partner Alex Bruce tomorrow.
Richard Naylor and Patrick Kisnorbo are still unavailable.
Grayson said: "It'll be highly unlikely that Andy will be in the team.
"We're still waiting to discover the severity of the injury – and it might just be slight cramp or a little tear – but the odds on him playing are quite short."
Becchio suffered his injury during Leeds' 4-0 rout of Scunthorpe United last Saturday, but Grayson's decision to omit his leading goalscorer in midweek has given the Argentinian a chance of lining up against Pompey.
Grayson said: "Luciano's making decent progress and we'll see how he is."
On-loan Sunderland defender George McCartney was ineligible for Arsenal's visit to Elland Road having signed for Leeds after the initial third-round tie in January 8, but he is vying to reclaim his place at left-back from Ben Parker tomorrow.