The Staggies are in need of a result in this contest to boost their chances of remaining in the division, whereas St Johnstone can play without fear in the knowledge that their top-tier status is secure.
Match preview
Ross County fell to their maiden defeat in the post-spilt schedule on Saturday as they narrowly lost at Fir Park against Motherwell - although the visitors were just moments away from escaping with a point.
Keith Watson was judged to have handled the ball in the area in the 99th minute, and after VAR checked the decision, the impressive Kevin van Veen made no mistake with his finish from 12 yards to secure all three points for the hosts.
The Staggies' back-to-back successes against Livingston and Dundee United to begin their Relegation Group campaign mean they still have a chance of avoiding the dreaded drop and a season in the Scottish Championship for the first time since 2019.
Malky Mackay's men are sitting inside the relegation-playoff position with just two matches left to play, albeit only a single point behind Kilmarnock - a side County travel to face on Sunday afternoon.
Jordan White was the hat-trick hero in the Staggies' 3-1 victory at Dundee United just over a week ago - the 31-year-old will be County's most-obvious attacking threat on Wednesday night.
St Johnstone travel to Dingwall on Wednesday knowing their Scottish Premiership safety is guaranteed following a 1-0 win at Kilmarnock on the weekend, with that success on the road being their first since February.
Skipper Liam Gordon popped up with the all-important goal after Graham Carey delivered an enticing corner, ensuring that Steven MacLean's charges will not be finishing the season inside the bottom in successive campaigns.
The Saints sit ninth overall in the Scottish Premiership standings, and although they are six points behind eighth-placed Motherwell with two games remaining, the message around the club is that standards cannot drop despite there being little to play for.
Having managed to score only 24 times in 38 league matches last season, St Johnstone have considerably improved in front of goal to ensure any fears of relegation could be squashed with two matches to play, with seven-goal striker Stevie May leading the side's scoring charts.
Although this term has not been as thrilling as St Johnstone's 2020-21 season in which they lifted both the FA Cup and League Cup, there will be a sense of satisfaction in how MacLean joined in April and steered the club away from relegation.
Ross County Scottish Premiership form:
W
L
L
W
W
L
St Johnstone Scottish Premiership form:
L
L
D
W
L
W
Team News
Ross County will have to do without the services of winger Owura Edwards on Wednesday night after the 22-year-old received his marching orders in the defeat at Fir Park on the weekend.
Alex Iacovitti was withdrawn 55 minutes into the contest against Motherwell and is a doubt for this one, meaning Dylan Smith could earn his first start since the Staggies' 6-1 defeat at Hearts in April.
St Johnstone boss MacKay has confirmed that midfielder Daniel Phillips has returned to training in the build up to the midweek trip to Dingwall - the Trinidad and Tobago international missed the victory over Kilmarnock due to a knock.
Chris Kane is another Saints player back in full training ahead of Wednesday night's match, with MacKay confident the attacker will play some part during the final two games.
One striker who will not be featuring until next season is 31-year-old Nicky Clark due to an ankle injury suffered in March - the former Dundee United man has struggled with knocks since making the switch from Tannadice last summer.
Ross County possible starting lineup:
Laidlaw; Watson, Baldwin, Smith; Randall, Kenneh, Tillson, Harmon; Dhanda; White, Murray
St Johnstone possible starting lineup:
Matthews; Brown, Gordon, Considine, Montgomery; McGowan, Wright, MacPherson, Ballantyne, Carey; May
We say: Ross County 2-1 St Johnstone
Ross County's first-tier fate is out of their own hands heading into the final two matches, although a clash with a safe St Johnstone side is a good opportunity to earn a much-needed maximum.