It leaves the Warriors without their two most experienced second rowers, with Thompson (143 games) joining 301-game veteran Ryan Hoffman (foot) on the injured list.
Also sidelined are halfback Shaun Johnson (knee) and props Albert Vete and James Gavet who both have broken arms. Johnson and Vete could be back for the final round, while Gavet is out for the season. Hoffman's return date has yet to be be determined.
It leaves the Warriors with a lack of firepower up front, for a potential banana skin game. The Warriors would usually be favoured to beat the hapless Knights - who have won only four games in the last two years - but the current form of both teams means that nothing is assured.
The Warriors are down on confidence are four consecutive defeats, with particularly poor efforts in the homes losses to the Panthers and Sharks. Whereas the Knights' young team appears to be on an upward curve; they were unfortunate to lose to the Bulldogs at Belmore four weeks ago, were competitive against the Broncos then upset the Dragons 21-14 last weekend, breaking an eight game losing streak.
The Warriors have won the last four clashes but the Knights have won two of the last three matches in Newcastle (2014 and 2015).
Hooker Nathaniel Roache has been included on the NRL side's extended bench after recovering from a hamstring injury picked up against Manly in Perth in round 17, while prop Charlie Gubb made a successful comeback from a hernia operation last Saturday, getting through 34 minutes in reserve grade.