GEELONG coach Mark Thompson says any move by the AFL to introduce a send-off rule would be nothing more than a knee-jerk reaction to a one-off incident.

In the wake of Barry Hall's seven-game suspension for punching West Coast's Brent Staker, the send-off rule has again been put back on the agenda.    

"I don't like compulsive change of rules and any change of rule should be well and truly debated and communicated. Just to change it on one punch would be quite silly," Thompson said.

With Hall out of the Swans' side to tackle Geelong at Skilled Stadium tomorrow, the premiership coach doubted the full forward's absence would dramatically alter the result.

"It might matter a little bit but I don't think it will be the difference between winning and losing for Sydney," he said.

"If they can win ball in the midfield and move it quickly, and they have been moving it a lot quicker, they'll have someone on the end of it. Whether he's good enough to mark the ball is anyone's guess."

Against a side the Geelong coach rates as a genuine premiership contender, Thompson is preparing for a hard slog despite the forecast of perfect conditions.

In the corresponding game last year Sydney restricted the Cats to their third lowest score of the season and outscored them eight goals to four after half time. Geelong fell over the line thanks to the individual brilliance of Gary Ablett and Steve Johnson.

"They've got the best defence in the competition and they really strangle you and make it hard to score," Thompson said of the Swans.

"We know exactly what type of game this is going to be.

"They make the finals every year and it wasn't that long ago they played off in two grand finals.

"They are just a hard and strong side and play a solid brand of footy that makes them really competitive and hard to beat."

Geelong made two changes to the side that defeated St Kilda last Saturday with running defender Andrew Mackie and young midfielder Brent Prismall coming into the side at the expense of the suspended Ryan Gamble and the unlucky Harry Taylor.

Thompson rated Taylor as "stiff" and said Gamble was as disappointed as anyone to be out suspended after working overtime to break into the premiership line up

Having won 23 of its past 24 matches Thompson said much of his coaching focus was on week-to-week planning and tutoring the players outside the club's best 22.

He said the side has as many as six players currently playing reserves football who were more than capable of matching it at senior level. 

"If you're talking about developing players to play footy then we've already got 23 guys who are experienced enough so we don't put a lot of time into them," he said.

"But we've got another 20 out the back that are going to have to play one day and we have to find out if they are going to be good enough. And then there's a level of education and knowledge you give your players when you play a team every week.

"Our output from the assistant coaches and the whole football club is exceptional and we strive to always be better and better and better with our preparation."