Cardiff captain Mark Hudson looks set to miss three to four weeks of action and may require surgery on his injured ankle.
The 30-year-old defender was forced off at half-time in the Bluebirds' 1-1 draw with Derby with an ankle injury which forced him to miss the victory over Sheffield Wednesday.
"There is a complication and that's something we are looking into," manager Malky Mackay told the South Wales Echo.
"There are conversations needed with our medical people and I can't put a timescale on when Mark is back.
"It looks at least three or four weeks, but we still have to make decisions."
Mackay loaned in Norwich defender Leon Barnett last week and the former West Brom man looks likely to be a regular in the skipper's absence.
Korey Smith is set to make his Oldham debut as Lee Johnson starts his managerial career at Boundary Park against Pools.
Smith has joined the League One strugglers on a one-month loan deal from Norwich and is fit to feature against John Hughes' side.
Johnson inherits a Latics side placed 21st in the table after he was confirmed as Paul Dickov's permanent replacement.
His first task will be to halt a run of three consecutive league defeats which has left his team two points from safety.
The youngest manager in the Football League will be without Matt Smith (knee) and Cliff Byrne (ankle) who both remain absent.
Johnson has no other injury or suspension concerns with Kirk Millar, Cristian Montano and Robbie Simpson all hoping for a change in selection under the new regime.
For the visitors, Hughes could pick the same starting line-up for the midweek encounter.
The Hartlepool boss has no new injury or suspension problems and could opt for the same XI that started in the narrow weekend defeat at Coventry.
That could mean a place on the substitutes' bench again for striker Steve Howard, who has yet to start a game since late January after shaking off a hamstring strain.
Antony Sweeney made his first start since January at the Ricoh Arena after his recovery from a knee injury and lasted 70 minutes. He is expected to resume in midfield alongside Ritchie Humphreys, Simon Walton and Jonathan Franks.
Teenage striker Luke James is pushing for a recall, but James Poole is likely to continue his partnership with Middlesbrough loanee Charlie Wyke up front.
Teenage defenders Jordan Richards and Jack Baldwin are out for the rest of the season with respective knee injuries.
