This time a year ago, the Buccaneers were praised for signing defensive end Michael Johnson, who developed into a double-digit sack man for the Bengals under Mike Zimmer's watch. Those same analysts were criticizing the Vikings for giving a similarly-sizable contract to Everson Griffen.

It turns out the Vikings got much more bang for their buck. Griffen had a team-leading 12 sacks and was a Pro Bowl candidate. Johnson, meanwhile, had just four sacks in his first season in Tampa Bay.

And, as it turns out, it was his last season in Tampa Bay, too.

The Buccaneers released Johnson yesterday, a year after agreeing to give him $43.75 million over five years (keep that in mind if you're upset the Vikings haven't made a splash in free agency). Because of offsets in the deal, the Buccaneers will pay Johnson $7 million in 2015 no matter what.

And now that he is back on the market, the Vikings are showing serious interest. According to my colleague Mark Craig, Johnson is scheduled to visit the Vikings in the next couple of days.

From a football standpoint, it makes sense beyond the obvious yet still noteworthy ties to Zimmer.

Griffen, their $42.5 million man, and Brian Robison, who turns 32 in April, were the starters a season ago. They spent a third-round pick on Scott Crichton, who rarely touched the field and watched the team activate Justin Trattou, back in 2015 on a futures contract, over him down the stretch. Veteran reserve Corey Wootton was a disappointment and is not expected to be back.

The Vikings, looking to improve their depth and possibly even find an eventual replacement for Robison, have showed interest in other defensive ends such as Adrian Clayborn in free agency.

Johnson, 28, is an explosive athlete in a 6-foot-7, 270-pound frame and is three years removed from an 11.5-sack season. Johnson has mostly played right end, the same position as Griffen, in his six NFL seasons, including the five he spent with Zimmer. But you have to figure Zimmer could find a role for him.

As is usually the case in this league, Johnson's potential cost could be a major factor.

The Vikings put a price on every player and perhaps he would consider a short-term prove-it deal because of those Buccaneers checks he will continue to cash. But if he wants another sizable pay day, it wouldn't make sense cap-wise unless the Vikings are ready to move on from Robison now.

Now I'm not saying that is the case. But it is worth noting that Robison is due a $2 million salary guarantee today and the rest of his $4.15 base salary will become guaranteed on July 1.

We will see how things go with Johnson's visit. He's believed to be the first free agent to fly in this week, and you've got to think Zimmer will try hard to not let him leave town without a deal.

What's left to be done for the Vikings? Check out their to-do list in our free agency tracker.