The Republic of Ireland international has been making progress on his hamstring injury and has returned to light training
The 28-year-old has been out of action since November and is due to make a second visit to a specialist in Germany, but has been able to return to light training, according to City assistant manager Craig Shakespeare.
"Sean has been able to get outside and do some training but he is not fully training," Shakespeare told reporters.
"Sean does tend to push himself and we will have to make sure that we hold him back a bit. He looks like he is progressing day by day, though," he added.
It had been initially feared that the centre back would miss out on Ireland's upcoming World Cup qualifiers, but the improvement in his condition will be a welcome development for Giovanni Trapattoni.
The Republic of Ireland squad will take on Poland on February 6 at the Aviva Stadium before their World Cup qualifying double header against Sweden and Austria on March 22 and 26 respectively.