Edwards, a free summer signing following his release from Notts County, has missed the last two matches due to a hamstring strain and fellow centre-half Murphy has been sidelined for a similar period with a calf injury.
The pair's absence prompted Abbott to draft in former Hibernian defender Sean O'Hanlon, who signed a deal until the end of the season earlier this month, and he has been partnering Danny Livesey at the heart of defence.
"Mike Edwards and Peter Murphy have both rejoined training this week so that's good news for them and us," Carlisle physio Neil Dalton told the club's official website.
A third defender, Chris Chantler, missed the home draw with Scunthorpe at the weekend due to a sprained ankle and remains doubtful for Saturday's league game at leaders Tranmere.
"Chris is our only other one (currently injured)," Dalton added. "He's continuing to have treatment on his ankle ligament sprain and we'll take it from there."
- Sports & Recreation
- Danny Livesey