Chelsea manager Jose Mourinho is waiting on the assessment of Michael Essien's knee injury sustained after the midfielder scored the winner against Birmingham.
Essien found the top corner at Stamford Bridge to help Chelsea set an English record of 64 unbeaten home matches in the league with a 3-2 win, but he then was substituted with 21 minutes remaining.
'It was something in the knee ligament,' Mourinho said.
'He was in pain, I had two midfielders on the bench so I made the change immediately.
'If you asked me, I don't know if he'd be fit for Wednesday against Reading.'
The positive news for Mourinho was Didier Drogba coming off the bench after missing the Community Shield through injury, while Joe Cole was an unused substitute.
Claude Makelele and Paulo Ferreira are expected to train today but Andriy Shevchenko is not ready to return yet following a reported back complaint.
Extending their home record will wait until later in the month as Chelsea travel to Reading on Wednesday and Liverpool next weekend.
Mourinho's personal record is even more remarkable and he will reach a century of unbeaten league matches at home if Chelsea avoid defeat against Portsmouth next time out at Stamford Bridge.
'I'm on 99 and I hope my friend Harry Redknapp doesn't kill my record in the next game at home because I would love to reach 100,' the Portuguese said.
Defeating Birmingham, however, was not straightforward after the visitors took an early lead through former Chelsea striker Mikael Forssell.
Claudio Pizarro and Florent Malouda marked their home debuts with goals but Olivier Kapo levelled matters before the break with a stunning strike.
Essien found the top corner five minutes into the second half and the attacking continued from both teams.
'It would be better to score five or six goals and win in a different way but the game was great, not just because Chelsea played great attacking football but because Birmingham also were great,' Mourinho added.
'Teams from the Championship, especially in the first period after promotion, come with a winning spirit because that is what got them promoted.
'They could have scored three and we could have scored six or seven.'
Birmingham boss Steve Bruce felt goalkeeper Colin Doyle could have done better with the goals from Pizarro and Essien - he got a decent hand on both - but was also encouraged by his team's performance on their return to the Premier League.
'We gave it a real go but unfortunately we gave away soft goals,' he said.
'When you come to Chelsea you need your goalkeeper to be your best player but he's had one of those days. But he was instrumental in us being here so he deserved to be in the team.
'It's great to be back, the atmosphere and the smell of the hot dogs. If we keep producing performances like that we'll make a fist of it.
'I've been here before and played 1-9-1 and it doesn't work. You have to score goals in the Premier League.'