I don't know what time span that will take from there, it depends how well he does.Steve Cotterill
The on-loan Arsenal right-back suffered a dislocated shoulder just 33 minutes into his Blues debut against Reading back in August.
He subsequently underwent surgery and has been working hard to get back to full fitness.
"He (Jenkinson) has started joining in training," said Blues boss Cotterill.
"I don't know what time span that will take from there, it depends how well he does."
Meanwhile, several of the other sidelined players are continuing to make good progress.
Midfielder Jason Lowe (hamstring), Craig Gardner (calf), David Davis (knee) and Stephen Gleeson (quad) are all back in training and Cotterill says that their return to first team action is also dependent on how well they acquit themselves out on the pitches.
Maxime Colin (hamstring) is also not too far away, according to Cotterill.
"He (Colin) said six-to-eight weeks, whereas we thought it might be four-to-six,” added Cotterill.
"He probably told you six-to-eight weeks, so when he is back in six he looks like a superman.
"I have already told him that as well!
"He is doing great, he is a great lad. It was a blow when we lost him.
"But they have been in the oxygen chambers hoping to speed up the process.
"He is back doing more active things but just not back to training yet.
"Slowly he will be coming back, and we have just got to make sure we are careful with things.
"To be fair to Emilio (Nsue), he has gone in and done very well in the last couple of games."
That just leaves striker Isaac Vassell (cruciate ligament) on Blues' long-term injury list.