The only challenge that comes with Sprong's game is his lack of defense ability. He tends to be solely an offensive player who knows his strengths. With that said, he can still be very useful on the PP, with the extra attacker or late in games when his team is down by a goal. He can be relied on to score goals.
As of right now, the Canucks are $1.3 million above the cap ceiling, which means they would need to become cap-compliant before the regular season starts. Due to that, if they do work out a deal with Sprong, it likely wouldn't be more than $1-1.5 million for the season.