Positive news also surrounds centre Dale Rasmussen and lock Graham Kitchener who near returns in the coming weeks.
However, the Sixways chief is keen to avoid a repeat of the long-term injuries that blighted last season and will only consider players when he feels they are completely injury free.
Ruddock said: "Marcel is probably going to be another week. He has had a cast put on his hand which, if I really needed him, I could put him out there and he could play.
"The reality is, if he does take another knock or had situations where he pressurised that bone more than he wanted do, he could put his hand out for even more weeks.
"With Rico Gear, Miles Benjamin and Chris Latham fit; I will probably leave him another week and get him absolutely right.
"We can get him back in the fray in the next couple of games in the LV= Cup and the games after that. I feel that is the wisest course of action as tempting as I am to get him back in action straight away.
"We saw last year, with all the injuries we had in the backs, that forcing players into a situation when we could lose them for even longer is not something that we advocate and would subscribe to.
"Marcel will be disappointed if he doesn't get in the panel this week. But there is every chance he will be back next week.
"Olivier is running and changing direction, but he still has a little difficulty crouching and putting the knee into a certain position where it is still a little bit tender," added Ruddock.
"He should be, with a little bit of luck, one more week and maximum two weeks. We want to get him absolutely right, we have invested in him and he has been unlucky to pick up this injury.
"Olivier played 25 games last year in the French league. He is not the sort of guy who is injury prone. But he has had this injury which has needed to be sorted and we want him right so we can go from there."
Meanwhile, Ruddock has revealed he will sit down with Birmingham Solihull prop Ricky Davies in the next seven days.
Davies has been training with the club during the week and has impressed Ruddock with his character.
"I will sit down with Ricky next week and with Russell Earnshaw from Birmingham Solihull to have a chat and see if we can map something out in the future at some stage," said Ruddock.
"He has impressed me and is a really good lad. He is 29 and has been around the block and has a lot of good experience at Scarlets and in the Championship for a while.
"He has mileage on the clock in terms of game time and given the lack of tightheads around he is someone who is of interest to me.
"There could be something with him being involved at some stage, whether that is for an A game or more training. And obviously, if we had some injuries, we would look at someone like Ricky who is the right fit in terms of his personality and his values.
"I have been really impressed with him, in that he stuck with the Bees even though they have financial issues.
"He is comfortable with the situation, to be able to train with us, look to pick up an A game and possibly be in contention for us should we look to take someone on a more formal basis."
Worcester Warriors will announce the team to face Newcastle Falcons at noon on Friday.