Watts has missed the past two matches with an ankle problem, while McKenzie did not play against Port Adelaide at TIO Stadium last Saturday night due to a groin injury.
Football manager Josh Mahoney was hopeful that Watts and McKenzie would return this weekend.
“Both Jack and Jordie will be monitored during the week,” he told melbournefc.com.au.
“If they are able to complete the appropriate training sessions this week, they will be available to play against the Kangaroos on Saturday.”
Tough nut Luke Tapscott is a possibility to resume from a groin injury, which forced him out of the past two rounds.
Ruckman Mark Jamar will miss another three matches with a calf injury, after he reinjured it against Fremantle in round 17.
Forward Liam Jurrah (ankle) is still another two weeks away.
Key forward Mitch Clark, veteran Aaron Davey and ruckman Max Gawn will miss the rest of the season with foot injuries.
Defender Clint Bartram and the speedy Jamie Bennell will also be sidelined for the rest of 2012.
Melbourne’s first pick in last year’s NAB AFL Draft, Rory Taggert (back), remains out indefinitely.
First year player Josh Tynan (concussion) and rookies Kelvin Lawrence (calf), Jai Sheahan (ankle) are all chances to return.
Round 18 injury list
Clint Bartram (knee) - season
Jamie Bennell (knee) - season
Mitch Clark (foot) - season
Aaron Davey (foot) - season
Max Gawn (knee) - season
Mark Jamar (calf) - 3 weeks
Liam Jurrah (ankle) - 2 weeks
Kelvin Lawrence (calf) - test
Jordie McKenzie (groin) - test
Jai Sheahan (ankle) - test
Rory Taggert (back) - indefinite
Luke Tapscott (groin) - test
Josh Tynan (concussion) - test
Jack Watts (ankle) - test
