Johnson returns to the fold having become a father, after his girlfriend gave birth to a baby girl.
Bristol City head coach Lee Johnson will give captain Gary O'Neil chance to prove his fitness, after he tweaked his knee in Saturday's defeat by Brentford.
Johnson also said he could make changes after the loss, but confirmed there are no other major doubts.
Bristol City head coach Lee Johnson told BBC Radio Bristol:
"We have got to make sure that our big players turn up and put in good performances.
"They [Preston] have flaws and weaknesses like all clubs in the Championship and we can only exploit them if we are at it.
"We have to make sure that everything we do is positive and on the front foot. We have to be the best team on the day."

Hearings, opened days after the 1974 attacks, were not continued after the jailing of six men, whose convictions were later quashed.
After the men's release in 1991 the families of those who died began a campaign to get the inquests heard.
Coroner Louise Hunt is expected to deliver her decision later.
Birmingham pub bombings inquests: What we know
A total of 182 people were also injured in the bombings, on 21 November 1974 - then the worst terrorist atrocity on English soil.
At 20:17 GMT, a device exploded in a duffel bag in the Mulberry Bush pub in the Rotunda, in the city centre, killing 10 people.
Pub bombers 'will not be jailed'
Ten minutes later, a second bomb went off in the Tavern in the Town, leaving 11 more dead.
The IRA was believed to have carried out the bombings, although responsibility has never been claimed.
West Midlands Police said the investigation is still open but there has not been enough evidence for a prosecution.
Ms Hunt, the Birmingham and Solihull coroner, has reviewed a huge body of police evidence and heard submissions from the victims' relatives and other interested parties in February.
She is expected to deliver her decision at Solihull Council house, during a hearing that is due to start at 10:00 BST.
Julie Hambleton, whose 18-year-old sister Maxine died in the attacks, said she was "cautiously optimistic" about the inquests resuming.
Preston North End have Daniel Johnson and Simon Makienok back after missing Saturday's draw with Nottingham Forest.
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A coroner is due to rule on whether the inquest into the deaths of 21 people in the Birmingham pub bombings will resume.