Running the rule over all 16 clubs ahead of the 2018 season, the former Dragons and Panthers star also named Knights recruit Connor Watson as the man under most pressure to perform at the club, even ahead of high-profile signing Mitch Pearce.
Soward also backed young Storm half Brodie Croft to seamlessly slip into Cooper Cronk's shoes and help the club press for back-to-back titles.
n terms of the Warriors, Soward identified Green as the man to reverse the problems that have dogged the talent-laden, but underperforming, team in recent years.
"[The Warriors] have picked up Tohu Harris, Gerard Beale, Peta Hiku [and Adam Blair] who are all internationals [but] the big question every year is 'can they get it right'," Soward told NRL.com.
"Can they get this mix of talent versus game management versus control versus flair right, because if they do they're going to be lethal.
"They have a big out in Matulino going to the Tigers. Picking up guys like Tohu Harris is important. If they can get all this right the guy who can take them over the top is Blake Green.
"He was so pivotal last season for Manly and the style they played. He potentially could be the buy of the year. He's not as big a name as other guys that have moved clubs like [Matt] Moylan and [Cooper] Cronk and [Mitchell] Pearce but he provides an important stability to what is an unpredictable team in the Warriors."
Soward said if the Warriors could get the best out of what was likely to be a rotating cast of bench forwards and utilities – names like Agnatius Paasi, Leivaha Pulu, Albert Vete, Nathaniel Roache, Ata Hingano, Ligi Sao and Mason Lino – that would provide the platform for Green to combine with the likes of Shaun Johnson and Roger Tuivasa-Sheck and spark the Warriors into form.
"If they can … get that mix right and Blake Green providing the game management and allowing Shaun Johnson to go and just play rugby league – they could push for a top-eight spot," Soward said.
Green could prove a better foil for Johnson and Tuivasa-Sheck than what Kiwi Test pivot Kieran Foran did in his one underwhelming season at the club, Soward added.
"Blake Green provides a steady hand, understands when to kick, when to be able to make changes to the game plan on the run. That's because he's been in systems like Melbourne.
"He's been successful in England, been successful over here, got the best out of his body and game management style. I think he provides the key to getting the best out of Tuivasa-Sheck and Johnson."
Soward predicted another pair of halves – Titan Kane Elgey and Raider Aidan Sezer – would face immense pressure to keep their spots if they didn't recover from some middling 2017 form early in 2018.
At the other end of the spectrum, Soward reckoned young Storm half Brodie Croft would slip seamlessly into Cooper Cronk's shoes and even suggested the Storm could be the first team to win back-to-back titles since Brisbane in the early 90s.
"This could be the year we finally see someone go back-to-back," Soward said.
"Everyone will talk about the change from Cooper Cronk to Brodie Croft but you've still got Cameron Smith and Billy Slater, around them guys like Will Chambers and Ryan Hoffman coming back, and they pick up a guy like Sam Kasiano. There's no real weakness in this side.
"Croft will obviously have questions asked of him early on in the year but from everything we've seen of him he's a Cooper Cronk clone. Melbourne are looking formidable heading into the 2018 season."
At the Knights, Soward expected it would be new five-eighth Connor Watson – rather than high-profile recruit Mitch Pearce – under the most pressure given his relative lack of experience in the position and competition from young gun Brock Lamb.
"It's going to be interesting what Nathan Brown does with Connor Watson going forward, whether it's Brock Lamb to start because Watson is so versatile and can come off the bench and play hooker and give that spell," Soward said.
"Whether Brock Lamb starts on the bench some weeks and comes on at six and Watson goes into nine to give Danny Levi a break, we'll have to wait and see.
"Probably the guy under the most pressure is going to be Connor Watson. He's coming to a new club, hasn't played a lot of six where he's the guy every week at six so there's going to be a lot of pressure on him to run the ball and create points outside Mitchell Pearce."