Guus Hiddink still looks over his shoulder despite Chelsea's recent unbeaten run
Guus Hiddink has admitted Chelsea could become embroiled in a relegation battle with defeats to Everton and Arsenal in the next two games.
The champions of last season are 14th after 21 games, 12 points off their stated target of fourth place and just six clear of Sunderland, who occupy the final relegation place.
The Blues' predicament prompted Jose Mourinho's departure last month and Hiddink's appointment.
Chelsea are unbeaten in six games since Mourinho left, when they were one point off the drop zone, but the midweek draw with West Brom did little to ease concerns.
"It's reality," Hiddink said. "We were down when we started. We were one point off the relegation line, but now we have a little bit more room to breathe.
"We have two difficult games coming up - Everton, who have a very good away record - and then Arsenal.
"If you don't gather points there, you don't know what the others do. The Premier League can surprise you.
"There are 12 points difference to fourth place, which is Tottenham.
"We all like to look forward and to the top of the table, but also don't be unrealistic - you're six points off the line of relegation. That's also a fact.
"We have to work hard and be very concentrated and gather our points to step up.
"That's why it was a pity that in the 86th minute we got this draw against West Brom, which would've helped us a lot to go up."
The Chelsea interim manager says the uncertainty - including over who will replace Mourinho on a permanent basis this summer, plus the likely lack of Champions League football - makes transfer business difficult this month.
Asked if everything is on hold, the Dutchman said: "I think so. That's the reality of Chelsea nowadays."
Striker has been a position of focus in transfer speculation regarding Chelsea, with back-up for Diego Costa lacking.
Radamel Falcao (thigh) remains out, but when Loic Remy is fit Chelsea have no concerns up front, Hiddink says.
He added: "That's a little bit new for me. That's good.
"As long as this is happening (and Remy is fit) we are not very active in doing other things."
Eden Hazard remains out with a groin injury, but could return for the January 24 clash at Arsenal.
"He must have some tough training sessions in midweek; from (next) Tuesday to Thursday he must have intense training sessions," Hiddink said.
Meanwhile, Everton are hopeful they can tie up a deal for Leeds academy graduate Sam Byram after agreeing terms with the Sky Bet Championship club.
"There's been an initial approach but from there, for having conclusive news for our fans, is a long gap still," said boss Roberto Martinez.
"We don't do things quickly or panicky. If there's any signing to be made, he has to be the right character, the right addition and that will always be the case.
"At the moment we have to be very careful. I don't enjoy the window clashing with important games.
"Leeds have important games now and we have important games."
Three days after their goalless draw at Manchester City Everton head to Stamford Bridge to face a Chelsea side whom they beat 3-1 - thanks to a Steven Naismith hat-trick - back in October when Jose Mourinho was still in charge.
Hiddink is now in temporary charge and despite some indifferent results all season Martinez is still wary.
"Chelsea are a team full of winning footballers," he added.
""Remember that they won the Premier League last season and that wasn't long ago. So the quality is there and they have players that in one second can produce a moment of magic."