After Sheldon Richardson's departure to Minnesota left a void in the interior of Seattle's defensive line, the Seahawks reinforced that spot by signing former Vikings tackles Tom Johnson and Shamar Stephen.

That's why coach Pete Carroll described it as a two-for-one swap.

In terms of price, though, the Seahawks actually signed Johnson and Stephen for a little over half of what the Vikings are paying Richardson. All three players got one-year deals. Richardson's has a base value of $8 million while Johnson's and Stephen's are each worth $2.1 million.

That doesn't necessarily mean the Seahawks got the better end of the swap. Richardson, after all, has perhaps the best résumé and most upside of the three, even if he didn't make as many impact plays in his lone season in Seattle as many had hoped.

But going from Richardson to Johnson and Stephen follows a pattern of the Seahawks replacing free-agent departures with veteran stopgaps on short-term deals worth considerably less money. That's what they did at tight end with Jimmy Graham and Ed Dickson and at wide receiver with Paul Richardson and Jaron Brown. Seattle also signed guard D.J. Fluker for $1.5 million after giving $7 million guaranteed last year to Luke Joeckel, who isn't expected to return.

Sheldon Richardson was a three-down player for the Seahawks who played around 60 percent of their defensive snaps last season, third-most among the team's defensive linemen.

The 33-year-old Johnson started 15 games for Minnesota last season, but recent comments from Carroll and general manager John Schneider made it clear that they want him playing a reduced role for Seattle as a rotational pass-rusher. From the sounds of it, Stephen has the inside track at replacing Richardson as a starter in Seattle's base defense next to Jarran Reed.

"Tom played almost 70 percent of the time for them, so he was in and out of all situations," Carroll told 710 ESPN Seattle. "I think we can really utilize him for his quickness and his pass rush to accent that in the rotations. We're not really concerned yet about the numbers of the percentage of plays, but I see him being a great rotation guy."

Carroll described the 27-year-old Stephen as fitting the mold of what the Seahawks have had in previous defensive tackles who have filled the three-technique spot on early downs.

"When you watch the Vikings, you see those two guys playing all over their film, and that's a great defensive line group, it's a great defense in the league and now they're on our club," Carroll said. "So I'm really fired up about it."

Below is a breakdown of the contracts for Stephen and Johnson.

Shamar Stephen

• Salary-cap number: $2.1 million

• Base salary: $800,000

• Signing bonus: $1 million

• Roster bonus: Up to $300,000 ($18,750 for every game on the 46-man active roster)

Tom Johnson

• Salary-cap number: $2.1 million

• Base salary: $950,000

• Signing bonus: $900,000

• Roster bonus: Up to $250,000 ($15,625 for every game on the 46-man active roster)