McEvoy has missed the past six matches with a hamstring injury, forcing the 189cm Blake to shoulder the bulk of the ruck work in his and Rhys Stanley's absences.
On Thursday morning, McEvoy boarded a plane for Adelaide, joining the squad to take on the Crows on Friday night.
Watters said McEvoy could learn plenty from Blake.
"I've sung Blakey's praises a number of times. He is an outstanding clubman. Maybe it's a challenge for Ben McEvoy to have a look at what Jason Blake has done over the last three or four weeks and elevate his performance as a ruckman and carry the ruck stocks," Watters said before boarding the plane at Tullamarine airport.
"There's a challenge there for Ben to step up. It's his first game back but I do expect big things for Ben going forward."
Joining McEvoy on the flight were defenders Sam Fisher and Jarryn Geary, who are both set to return from injury.
Fisher was close to returning for the round eight game against West Coast but had to wait a further four weeks before making his comeback.
Watters said the Saints chose to take a conservative tact with Fisher, who took longer than expected to recover from a hamstring injury.
"We probably thought he might have been a week or two earlier but he is such an important asset to us that there was certainly going to be no risk going forward. But he is available and we look forward to him having an impact," he said.
The Saints have not had the same result for two consecutive weeks since back-to back wins against Gold Coast and the Western Bulldogs in rounds two and three.
Watters said inconsistency was not a problem however, with the Saints showing plenty of good signs in the games they'd conceded.?
"I don't buy into the inconsistent line. On the surface, you can look at the win-loss-win-loss, I understand that," he said.
"But our effort and ability to stay in games, even games we've lost, we've been right in those games into the last quarter. I think our effort and performance has been pretty consistent across the year. It's not the win-loss ratio we'd like but I can't fault their effort."
Luke Holmesby covers St Kilda news for AFL.com.au. Follow him on Twitter - @AFL_Luke
