According to Heat, Nicola Roberts, Sarah Harding, Kimberley Walsh and Nadine Coyle have met up in the studio and are "really up" for a 2012 tour to mark their 10th anniversary.
An alleged source told the publication: "The girls are very keen to reunite and start working on another album. Their main love is the band and they all feel ready to get back and start recording. But Cheryl can't commit to that right now."
Cole has been linked to a judging role on The X Factor USA and is also continuing with her solo career after releasing 3 Words in 2009 and follow-up Messy Little Raindrops last year.
The source continued: "They're all very supportive of her, but they are concerned they could be left behind. They're also worried they might be hanging around forever if they wait for Cheryl.
"Obviously it's going to be very difficult without Cheryl, but they know they'll do well with another album and Cheryl could even join them for the tour next year if she's available. It makes sense and it doesn't mean that she'd leave the band - she'd just be taking a break."
Coyle released her own solo album Insatiable last year but the record peaked at number 47 in the charts and she split from her management in February.
Meanwhile, Roberts is reportedly poised to release her own debut solo album later this year after working with Metronomy frontman Joseph Mount. Harding has acted in several feature films.
Walsh has recorded a track with Aggro Santos and has also been tipped to replace Konnie Huq on The Xtra Factor.
Asked if the band could continue as a four-piece, X Factor judge Louis Walsh - who managed Girls Aloud at the start of their career - said: "Absolutely. Westlife became more successful without Brian McFadden, and the Spice Girls did it without Geri Halliwell."