Roberts injured his hamstring in the 1-0 win at Reading at the end of November while Shackleton has also not featured since the victory at the Royals with the midfielder also having a hamstring issue.
But both are now set to train with the rest of the Whites squad next week while Bielsa also confirmed that skipper Liam Cooper was back from a calf strain ahead of Saturday's Championship clash at Fulham.
Adam Forshaw was the only injured player Bielsa was unable to provide an update on with the 28-year-old still recovering from a hip problem.
"Cooper is back," said Bielsa, speaking at Thursday afternoon's pre-Fulham press conference.
"Tyler is healthy. Shackleton also. Forshaw there is no different information."
Asked when Shackleton and Roberts were expected to return, Bielsa revealed: "Next week they will train with the team."