Celtic manager Neil Lennon admits he will need to be patient in the full-back department as he continues to look for reinforcements and give Kieran Tierney time to regain fitness.
Tierney underwent hernia surgery in the summer but is still working to overcome pelvic problems, and Lennon will need to find another left-back for Wednesday's Champions League return against Sarajevo after Boli Bolingoli got injured in the first leg.
Centre-back Kristoffer Ajer filled in at right-back during Celtic's 3-1 win in Bosnia as Lennon seeks a replacement to Mikael Lustig.
When asked about Tierney, who had several spells out last season, Lennon said: "He's still injured. He is rehabbing. He had the double hernia and he still has the osteitis pubis problem, so it's a slow burner."
On Bolingoli, Lennon said: "He's OK, he rolled his ankle. Whether he will make the second game is debatable. Mikey (Johnston) will miss Sarajevo with a (thigh) strain but should be back for the second round."
Lennon admits his search for a right-back could take more time.
He said: "We are trying to get it down to the quality of player we want, and does he fit our profile with age and the attributes we want from a full-back.
"They are difficult to find because we have been looking for a while. Ideally, we would like to bring two in. It's a slow process.
"It's still very early. A lot of teams are just back and weighing up their squads. It's not as if you can do all your business right away. We need to have patience.
"We have done good business so far, we will make additions and maybe see some players go the other way, but that's a process that takes time. I think there is a bit of trimming to do."
Lennon's two other summer arrivals, defender Christopher Jullien and midfielder Luca Connell, are set to feature in Saturday's Parkhead friendly against Rennes.