Just when things were getting brighter for the Minnesota Vikings, they received a massive blow that could wreck their momentum.

Star quarterback Kirk Cousins is confirmed to be out for the rest of the season after tearing his right Achilles tendon over the weekend.

The injury, which occurred in the fourth quarter of their win against the Green Bay Packers, came at a time when the Vikings were on a roll, having won four of their last five games.

"We're all hurting for Kirk," Vikings coach Kevin O'Connell told reporters, "just knowing how much he's invested into this team."

The team previously speculated an Achilles injury, and it was confirmed after Cousins underwent an MRI.

He will undergo surgery, although the date has yet to be determined. The timeline for his recovery is also TBD.

Replacing Kirk Cousins will be hard

Cousins' caliber is not easy to replace; thus, Vikings coach O'Connell is having difficulty choosing who will do the quarterbacking for them from here on.

Fifth-round pick rookie Jaren Hall took over for Cousins when he went down and was forced out of the game, but O'Connell remains mum whether he will be the regular QB.

The coach revealed that he has been receiving calls about possible Cousins replacement. However, they are still mulling over whether they will sign an instant backup or invest in the future, too, with Cousins set to become a free agent soon.

"Is it a short-term only thing? Is it something that could be more long term? Is it something that truly is an upgrade versus just the sheer dealing with the reality of a tough situation right now?" O'Connell said. "That's what we have to work through."