O'Neill will be hoping for better fortune this time. He joined them in January of last year but was forced off injured before half time on his debut against Chesterfield and didn't make another appearance for them.
He enjoyed loans last season with both Scunthorpe and Leyton Orient but has now returned to Southend and manager Phil Brown who said some weeks ago that he was keen to get him again.
It makes him available for their game tomorrow against Swindon although there has been no confirmation as to how long the loan will be. The maximum period for an emergency loan is 93 days with a minimum of a month.
The 24-year old O'Neill joined Burnley from Mansfield in the summer of 2012 but has made only two first team appearances. He played against Plymouth in the Capital One Cup early in his first season and he ended that season with a late substitute appearance for Kieran Trippier in a 2-0 home win against Ipswich.
He's down the pecking order for the right back position right now with fit again Matt Lowton, Tendayi Darikwa and Cameron Dummigan all in front of him so this will give him an opportunity to play some first team football.
Update: Reports from Southend suggest the loan has not been completed although Burnley Football Club have confirmed it. The Southend Echo are reporting that it should go through tomorrow and hinted that the deal could be made permanent next week.