The Scorpions will travel to Hobart to take on Tasmania and Queensland this weekend.
Middle-order batter and leg-spinner O’Neil is yet to make her senior State debut, while medium-pacer Harris last played in November 2016.
Left-arm seamer Katelyn Pope remains in the squad after being named twelfth for both matches in round one and teenage off-spinner Shae Daly has been omitted.
“Annie O’Neil, Brooke Harris and Katelyn Pope are the three girls probably vying for that eleventh spot in the team, so they’ve been doing some great work over the last few weeks to put their hand up,” said vice-captain Tegan McPharlin.
With captain Megan Schutt absent due to Australian duties at the ICC Women’s World T20, McPharlin will assume captaincy for the weekend, after stepping down from the top job earlier this year.
“I’m looking forward to leading the girls (again),” McPharlin said.
“Obviously Megan’s away with the Australian team at the moment so I’m happy to step into the role for this weekend. It’s such a good bunch of girls.”
All seven teams notched one win and one loss in round one, meaning an even playing-field heading into round two.
“It’s a very even competition this year so we’re looking forward to playing Tassie and Queensland this weekend,” McPharlin said.
“If we could chalk up two wins, that would be fantastic.”
Round two WNCL fixture
Saturday 10 November, SA v Tas, TCA Ground, Hobart, 9:30am ACST
Sunday 11 November, SA v Qld, TCA Ground, Hobart, 9:30am ACST
Tegan McPharlin (c)
In: Annie O’Neil, Brooke Harris
Out: Shae Daly (omitted), Megan Schutt (World T20)