by Curtis Crabtree
KJR reporter
Twitter: @Curtis_Crabtree

RENTON - The Seattle Seahawks struggles on third down are no longer just an offensive issue. Well, it is offensive, but not in relation to that side of the football.

Seattle's defense has been suffering their own struggles at winning on third down. Earlier in the season, Seattle's offense was the focus for not being able to convert third down opportunities to keep drives alive. Now the defense is finding it exceedingly difficult to get off the field, even in favorable third-and-long situations.

The Detroit Lions converted 12 of 16 times on third down, including three times on their game-winning touchdown drive, in handing Seattle a 28-24 loss last Sunday.

"We made some mistakes that they took advantage of. Just little technical things like a guy dropping a bit out of his area, not picking up his leverage when it’s man to man the way we like it and things like that," head coach Pete Carroll said on Monday.

"We’ve missed hit a couple of pressures that we had a great chance to get something done on, but timing wasn’t great for us. They just took advantage of every one of them and they were so efficient down the stretch it just shows you that this was a really good quarterback that we played and he was able to carry it out through the game and get them a win."

Seattle ranks dead last defensively in the NFL in their official statistics for allowing plays on "third- and-long," which refers to "third-and-6" or greater. The Seahawks have allowed teams to convert 39.3-percent of attempts on third and long. The New England Patriots are 31st in the league at 37-percent.

The Seahawks have also allowed teams to convert 16 of 37 tries (43-percent) on third-and-10 or more. They are the only team in the league to have allowed double digits in third-and-10 or more conversions through eight weeks.

Overall, Seattle is allowing teams to convert 43.9-percent on third down, which is 27th out of the 32 teams in the league. Only Pittsburgh (44-percent), Minnesota (44.2), the New York Jets (45), Tennessee (45.7) and Buffalo (47.3) are allowing teams to convert more frequently on third down.

LB K.J. Wright said it's not something they're worried about because they know it's something they can get corrected.

"It don't worry me at all," Wright said. "I know we're a good defense and I know we can adjust to anything so I'm not worried."

Wright said it's partly an experience issue in getting used to see the various route combinations and being able to react faster to what they're seeing. Between Wright in his second year, rookie LB Bobby Wagner and CB Marcus Trufant adjusting to a new position, the Seahawks have been just out of position at times.

It's a chemistry that is still developing between the group.

"I recognized one (route combination) last week but it was a little too late and they got the first down so it just comes with experience. We'll be able to get the job done. We're still learning," Wright said.

The Seahawks placed WR Ben Obomanu on injured reserve Tuesday with a sprained wrist suffered against the Detroit Lions on Sunday. Obomanu tweeted that he could have played with a cast and would have been all right in a few weeks but the Seahawks weren't willing to wait for him.

Carroll on the other hand said that Obomanu would need to be in a cast for 6-8 weeks before being able to return.

Seattle promoted WR Jermaine Kearse from the practice squad to fill his spot on the roster. Kearse has been on the practice squad for most of the season and has looked good in practice in recent weeks.

With WR Doug Baldwin fighting to get back from a high-ankle sprain and WR Braylon Edwards' status uncertain with a knee injury, the Seahawks may head into Sunday's game with just four healthy receivers. If that's the case, Kearse will be thrust into action right way.

Carroll said Baldwin is doing better than expected and is trying to make it back this week. Edwards is expected to practice but Carroll said he was unsure of how he would respond after having his knee swell up before last week's game.

"We have to wait and see on Braylon," Carroll said. "We have to wait and see if Doug can make it back, and the rest of the guys are ready to go, and of course, Kearse is jacked up about the opportunity."

Carroll was somewhat optimistic about the progress from Baldwin after calling him a "long shot" to play on Monday.

"He looks better than we expected coming into the week," Carroll said. "I don't know if that's going to happen or not, but we're going to see."

In addition to the receiver swap, Seattle also added T Michael Person from the practice squad and waived CB Danny Gorrer. The Seahawks then added WR Phil Bates and WR Lavasier Tuinei to fill the vacancies on the practice squad.

Both Bates and Tuinei were with the Seahawks throughout training camp and are familiar with Seattle's offense.

The Tampa Bay Buccaneers claimed Gorrer off waivers Wednesday.

Injury Report:

Minnesota Vikings

Did Not Participate

TE John Carlson (concussion)
LB Tyrone McKenzie (non-injury)

Limited Participation

WR Percy Harvin (hamstring)
CB Antoine Winfield (knee)
S Mistral Raymond (ankle)
RB Adrian Peterson (ankle)

Full Participation

DT Fred Evans (knee)
DT Letroy Guion (ribs)
LB Erin Henderson (elbow)
P Chris Kluwe (knee)
QB Christian Ponder (knee)

Seattle Seahawks

Did Not Participate

DT Jason Jones (ankle)
WR Braylon Edwards (knee)

Limited Participation

WR Doug Baldwin (ankle)
G John Moffitt (knee)
CB Byron Maxwell (hamstring)

Full Participation

RB Marshawn Lynch (back)