As someone who has been a punter for 45 years, and worked for a large Bookmaker for 13 years, I have to disagree with you, and agree with
@KLo30.
Thunder are currently $1.72 fav, in a market set to 105.1%.
Sams is currently $2.10 fav to be Thunders leading wicket taker for the tournament.
Chris Green is currently $6.00 2nd fav to be Thunders leading wicket taker for the tournament.
If you think taking the 2 players expected to be their leading wicket takers out of their team, won't shift the betting line, you're crazy.
As to proposition betting, Sams is currently $3.75 fav to be the leading wicket taker for Thunder, for this match. The market is currently set to a poisonous 192.5% and Sams coming out would see all other players prices drop by roughly 20-25%, if they decide to keep the market
that poisonous!
My guesstimate is, that if Sams is confirmed as not playing, Thunder could get out to $1.80. If Green was to be added as a confirmed out, that might be $1.82. There is a huge difference between $1.72 and $1.82. The biggest difference in those prices is reflected in the Stars price, which would shift from $2.13 into $1.98.
Punters are very re-active, and usually they over-react. I can't see Bookmakers have set their current prices with the expectation that Sams isn't playing. That could cause problems for them if/when he does. It is possible they have shaded the odds slightly, in case he is out, but only very marginally.