Blues general manager Doug Armstrong must solve his salary-cap puzzle from the goal line out.

His biggest piece, by far, is goaltender Jordan Binnington. As a restricted free agent he will multiply the $650,000 salary he earned last season after finally graduating from the minors. That math will dictate what’s left for others.

The bargaining process continued Friday, when Binnington filed for salary arbitration — along with defenseman Joel Edmundson, the team’s second-largest puzzle piece, and forwards Oskar Sundqvist and Zach Sanford.

The Blues had about $14 million in cap space Friday afternoon, enough to keep most of their Stanley Cup-championship roster intact. But even with veteran defensemen Jay Bouwmeester and Carl Gunnarsson taking salary cuts, there probably isn’t enough for everybody.

(Fans proposed trading goaltender Jake Allen to create cap space, but that wasn’t happening. Allen is a good fit for the team. There wasn’t a trade market for him this summer because few teams sought a change in goal. And replacing Allen would have been costly.)

This cap crunching brings us to winger Pat Maroon. He accepted a pay cut last season to come home to St. Louis and be with his son, Anthony. He also hoped to command bigger dollars on his next contract after earning $1.75 million this season.