Rick Spielman was a busy man Monday. A busy general manager who also had a productive day in making defining personnel moves.

A flurry of activity that included the Vikings and quarterback Kirk Cousins agreeing on a two-year extension was punctuated by a late-night doozy: Trading disgruntled wide receiver Stefon Diggs to Buffalo for a significant haul that includes a 2020 first-round pick

Well done, Trader Rick.

Now fix the offensive line.

Cousins’ extension was widely expected because the Vikings were mired in salary-cap quicksand and needed relief to make necessary improvements.

Unloading Diggs figured to be more difficult because he is a star, the roster isn’t exactly stocked full of receivers and the Vikings couldn’t afford to just give away a player of Diggs’ caliber simply because he’s unhappy, which he voiced in another social media post hours after Cousins’ extension became public.

Spielman played his Percy Harvin card at the scouting combine by saying “there’s no reason to anticipate [Diggs] is not going to be a Minnesota Viking.”

He should have finished that sentence with a wink. There were plenty of reasons to believe Diggs wouldn’t be a member of the organization this season. Remember his work boycott this past season that cost him $200,000 in fines? And his weird cryptic messages on Twitter?

Diggs’ post Monday about “time for a new beginning” seemed like a final salvo. He got his wish. Final summation on Diggs: Great talent, one miracle moment but also a lot of drama. The Vikings landed in a good spot.

The trade netted four draft picks, including a second first-rounder in this draft. Spielman now holds real draft capital that can be used to fill pressing needs.

Cousins’ extension assures him more time in Minnesota. Does that mean Spielman and coach Mike Zimmer are next in line? Seems likely, if only adding one or two more seasons to their deals. The fate of all three are superglued together.

The anti-Cousins crowd will howl in frustration over his extension, but the tradeoff was worth it. The Vikings had no salary cap room. They jettisoned defensive fixtures Xavier Rhodes and Linval Joseph last week but that was a start, not a full accounting. Extending Cousins lowers his 2020 cap number by about $10 million.

The Vikings entered the offseason with an extensive to-do list. At the top:

No. 1: Create cap flexibility. No. 2: Upgrade the offensive line. No. 3: Decide if Diggs has a future here.

They have accomplished two objectives so far. Bolstering the line is paramount.

Cousins had a career year statistically last season. He won a playoff game in New Orleans, thus altering his narrative about not being able to win a big game. But his weaknesses are well-established by now, as well.

He doesn’t improvise well when the pocket collapses. He becomes jittery when facing constant pressure. Bad attributes to have with a subpar line.

Cousins thrives when conditions are favorable. We’ve seen him carve up bad defenses or when he has solid protection, but the road to a championship isn’t paved with patsies. He looked completely overwhelmed against the ferocious 49ers pass rush.

The Vikings need a minimum of two new starters on the line. Clear upgrades, not lateral moves with different names. If the Vikings don’t have a mobile quarterback skilled at making something out of nothing, they better have a stalwart line that insulates him in order to maximize his strengths. Otherwise, their plan isn’t going to work.

There are those who wanted the Vikings to stand pat on Cousins, draft a quarterback with a top pick this spring and start the process over. If they can identify a QB of the future who they fully believe in, go for it, even with Cousins’ extension. But again, that requires long-term security at the top.

Allowing a GM and head coach in the final year of their contracts to draft a franchise quarterback is a recipe for future problems. Of course, trading Diggs seems counterintuitive to a win-now mentality, but with or without an extension, Spielman and Zimmer are not inclined to start over with a rookie quarterback and likely suffer through growing pains.

The Vikings remain committed to Cousins. If they don’t adequately address needs around him — which now includes wide receiver, along with offensive line — it will just be more of the same.