Murphy had an operation on his patella tendon after last season and has been nursed through the pre-season.
"We said last week it would be round four, and whether that's with Williamstown or with us, only time will tell," coach Rodney Eade said on Wednesday.
"In the pre-season he was about three weeks ahead of schedule so that's why we thought he was a chance for round one.
"The specialist always said round four or five.
"The game he played in the NAB Challenge in the wet put him back a bit, so we're looking at next week."
Eade said he was not planning many changes for the clash with Richmond on Monday but expected elevated rookie Liam Picken to play his second game after an impressive debut last weekend.
He also said it had been pleasing to have a variety of goal scoring options in the absence of Murphy and with Scott Welsh and Jarrad Grant playing in the VFL.
"We've been able to kick some goals. Obviously it was wet at the weekend, which limited that, but we were certainly able to create enough scoring opportunities," he said.
"Murph's got to come back in, Adam [Cooney] is going to become a better player as the year goes on and starts picking up his match fitness, so that can add another dimension to our forward line.
"Welsh has got to come back in as well. He's starting to hit some form, which is good.
"Then there's Jarrad Grant and some tall young players who are developing.
"It will depend on opportunities for them. There's Scott and Jarrad, but when people are playing well, it's hard to make a spot for them. They'll just have to keep hanging in there until an opportunity arises."
Eade said the players had recovered well from their round one trip to the west and last weekend's soggy clash with North Melbourne, and were expecting a tough contest from the buoyant Tigers.
"We thought they may have been struggling to Thursday or Friday because they only played on Sunday but most of them are fine today, which is a good sign," he said.
"Richmond would have gained a lot of confidence from the weekend.
"The first round was a bit of an aberration, really, based on what people expected pre-season with the talent they've got in their list."
