The Take That star's wife Dawn is due to give birth to the couple's fourth child in early October, according to The Sun.
However, during negotiations with ITV earlier this week, Barlow allegedly assured bosses that he will return to the panel later this year.
"Everyone was delighted Gary agreed to come back for another series of X Factor," a source claimed. "There's no ink on the contract, but he's good for his word."
"He was being a bit sheepish about his decision though because the diary has kicked up some problems," the insider added.
"Gary has promised he'll be present for the birth, but Simon Cowell is a tough task master. It could be very tricky."
Questions have also been raised over whether Barlow can appear in the competition's auditions stage because of his commitment to the Queen's Diamond Jubilee celebrations in June.
Cowell previously stated his intention to lure back all four judges - Barlow, Tulisa Contostavlos, Kelly Rowland and Louis Walsh - for series nine of the ITV talent show.
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