Port Vale have sacked manager Andy Crosby just two weeks before the rescheduled meeting between the two in Berkshire.
Crosby, a former Royals assistant manager in the Premier League under Nigel Adkins, was dismissed following a 3-0 defeat to fellow relegation candidates Fleetwood Town.
Only taking over permanently in the summer, the Staffordshire side are without a win in their last four and sit two points- and one place- above the Royals.
The Valiants travel to the SCL Stadium on Tuesday, February 20. This is a rearranged fixture after the original clash was abandoned due to supporter protests on the pitch.
This will be the second club the Royals face this month who have recently changed managers, with Charlton Athletic's first match under former Luton Town boss Nathan Jones coming on Saturday in RG2.
Ruben Selles, Neil Critchley of Blackpool and Neil Collins of Barnsley are the only three bosses appointed over the summer who are still in their roles, with Matt Taylor of Shrewsbury Town replaced by Paul Hurst earlier in the month.
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