The versatile midfielder has been missing for an extended period after receiving surgery on an injured shoulder.
"It’s great to hear that," Phillips told Football Insider on O'Nien's injury update.
"It will be a big boost when he’s back. To get back a player of his versatility ahead of the business stage of the season will be fantastic.
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“He’s a good lad to have around the squad day in and day out. I have always spoke very highly of him. To get him back would be a great boost for Lee both on and off the pitch.
“He will have a major role to play between now and the end of the season.”
Dion Sanderson signs for QPR
Ex-Sunderland loanee Dion Sanderson has signed for QPR on loan.
The central defender spent last season at Sunderland and the first part of this campaign at Birmingham City before returning to parent club Wolves.
But Sanderson, 22, has now joined the London club until the end of the season with the Championship club fighting for promotion at the top of the table.
“I am really pleased we have been able to bring Dion in,” QPR boss Warburton said.
“We need to have competition for places and he certainly brings that because he has the quality to play anywhere across the back three.
“He played against us earlier in the season at home and he showed his quality on the left side. More recently, he played against us for Birmingham in the away game and was very strong on the right.”
He added: “He drives into midfield, he can see a pass, his all-round game is very good and he is only going to get better.
“He is solid, quick, a good athlete and comfortable on the ball, so he was an immediate target for us.
“I am delighted to have him with us.”
Sanderson is fit and available for selection for Saturday’s home fixture with Reading in the Championship and will wear squad number 28 upon his arrival.