The Jamaican international has not figured for the First Team since netting in the 2-1 victory over Ipswich Town on 13 December.
Last season’s top-scorer has completed 45 minutes in each of the last two Blues Development Squad games, where he also registered a goal in both.
“Clayton will be in the squad tomorrow which is very good news,” confirmed Blues boss Gianfranco Zola.
“He is much better and catching up (fitness-wise).
“It’s just about finding the right moment to put him back in the team."
Full-back Cheick Keita is back in training after missing last weekend’s trip to Cardiff City with a knee injury.
“He (Keita) trained this morning, so he is fit in terms of medical fitness, but in terms of condition I don’t know because he didn’t train for most of the week so I will decide tomorrow,” said Zola.
If Keita is not quite ready to return, Zola says he is happy for Jonathan Grounds to continue.
“Jonathan did very well and I was pleased with his performance, so there is a strong possibility he will be back in the position again.”
Meanwhile, central defender Michael Morrison has suffered a slight set-back in his return to fitness following groin surgery at the start of February.
He went in for a minor bout of surgery this week after complications following an initial groin operation.
It has set him back another week or so on the road to recovery.