Will Grigg to sit out Northern Ireland's meetings with San Marino and Germany
Will Grigg will not feature in Northern Ireland's World Cup qualifiers against San Marino and Germany after asking to sit out for personal reasons.
The Wigan striker has recently had a child with his partner and that is understood to be the reason behind his request.
The 25-year-old, who became a cult hero at Euro 2016 due to the Green and White Army's infectious 'Will Grigg's On Fire' chant, despite the fact he did not play a minute, has been in good form this season with six goals in 11 appearances for the Latics.
"Will Grigg has asked to not be in the squad due to a family situation which I'm not going to go into. It's his decision," said O'Neill.
"It's a blow for Will. He 's been on the scoresheet but I had a good chat with him and he didn't feel being here was right."
Grigg was left out of the starting XI by Wigan boss Gary Caldwell against Wolves in midweek and, although he came off the bench and netted in a 2-1 win, his manager explained: "I just felt Will looked a little bit jaded in the last few games, he didn't look his normal sharp self.
"His girlfriend has just had a baby, and obviously with all that emotion, and the different things that go along with that, I thought it was the night to give him a rest."
That rest will now spill over to international week, with Northern Ireland hosting San Marino at Windsor Park on October 8 before travelling to play the Germans three days later.
O'Neill's 24-man squad is otherwise at full strength, with Shrewsbury defender Ryan McGivern and Rochdale midfielder Matthew Lund returning to the set-up.
Burton defender Tom Flanagan is back after injury forced him to reject a maiden call-up for the goalless draw in the Czech Republic earlier this month.
He was replaced in that squad by Aberdeen's Calum Morris, who has not been retained, with Dundee's Celtic loanee Michael Duffy also dropping out.
Kyle Lafferty, whose goals fired O'Neill's side to their first ever European Championship in the summer, is one of four specialist strikers but has managed just 46 minutes of first-team football for Norwich since leading the line in Prague.
His starting spot will be challenged by Conor Washington, Josh Magennis and Liam Boyce.
Assessing the wildly different calibre of opposition awaiting his team - probably the easiest and most difficult assignments of the group in the space of 72 hours - O'Neill said: "San Marino offers us a chance for three points. Anything we take from Germany is a bonus, it's like facing Barcelona.
"The game against San Marino will be about how to attack and Germany will be about how to defend. It's a big switch."
Northern Ireland squad: M McGovern (Norwich), A Mannus (St Johnstone), T Carson (Hartlepool), G McAuley, J Evans (both West Brom), C Cathcart (Watford), C McLaughlin (Fleetwood), L Hodson (Rangers), M Smith (Peterborough), T Flanagan (Burton), R McGivern (Shrewsbury Town), S Davis (Southampton), N McGinn (Aberdeen), O Norwood (Brighton), C Evans (Blackburn), J Ward (Nottingham Forest), S Ferguson (Millwall), S Dallas (Leeds), P McNair (Sunderland), M Lund (Rochdale), K Lafferty (Norwich), J Magennis (Charlton), C Washington (QPR), L Boyce (Ross County)