Grigg scored his only international goal in the friendly win over Belarus in May of last year
Will Grigg has again been left out of the Northern Ireland squad for next month's World Cup qualifiers against San Marino and the Czech Republic.
Grigg, who is on standby, has not featured since last November's friendly against Croatia.
The Wigan striker has made five club appearances this season although he has only started in two EFL Cup games.
Liam Boyce is ruled out by a knee injury while Gareth McAuley also misses out because of a thigh problem.
Bradford City striker Shay McCartan is preferred to Grigg after winning his first cap in the friendly against New Zealand in June.
Boyce ruptured his anterior cruciate ligament while in action for new club Burton in a pre-season friendly while McAuley has not played since exacerbating a thigh injury in Northern Ireland's qualifier win over Azerbaijan in June.
QPR's Conor Washington is recalled after he missed the last qualifier to get married and Corry Evans is another addition from the most recent squad having overcome a groin injury.
Watford defender Craig Cathcart is also back after missing the games in June but Sunderland's Paddy McNair (knee) and Nottingham Forest's Jamie Ward (calf) remain out because of injury.
Manchester City target Jonny Evans has missed West Brom's opening two games because of a hamstring injury but is included included in O'Neill's 25-man squad.
Northern Ireland, who face San Marino away on 1 September before hosting the Czechs three days later, are second in Group C and on course for a play-offs spot.
With four rounds of fixtures left, world champions Germany lead the table on a maximum 18 points with Northern Ireland five points off the place and the Czechs a further four points adrift in third spot.
Northern Ireland squad
Goalkeepers: McGovern (Norwich City), Mannus (St Johnstone), Carroll (Linfield)
Defenders: Hughes (Hearts); Evans (West Brom), Cathcart (Watford), Brunt (West Brom), C McLaughlin (Millwall), Hodson (Rangers), R McLaughlin (Oldham), Thompson (Bury), D Lafferty (Sheffield United), Flanagan (Burton Albion)
Midfielders: Davis (Southampton), McGinn (Gwangju), Norwood (Brighton - on loan at Fulham), C Evans (Blackburn), Ferguson (Millwall), Dallas (Leeds), Lund (Burton Albion), Paton (St Johnstone)
Strikers: K Lafferty (Hearts), Magennis (Charlton), Washington (QPR), McCartan (Bradford City)
Source: bbc.com