The sledding gets much tougher for Survivor Pool players as the season goes and top teams fall off the list. Week 13 presents a vast number of options, with four teams favored by double-digits on Sunday. But lasting deep into the season isn't about just picking the biggest favorite each week, and that strategy doesn't work anyway. Just ask the Vikings, who lost at home by three touchdowns as 17-point favorites against the Bills. Or ask the Saints, who lost by eight to the Bucs in Week 1 as 10-point favorites and fell to the Cowboys on Thursday Night Football despite being favored by more than a touchdown.

Before making your NFL Week 13 Survivor Pool picks, you'll want to hear what SportsLine's Mike Tierney has to say. The national sportswriter who has reported from seven Super Bowls whose work has appeared in the New York Times and Los Angeles Times, he has his finger on the pulse of the league.

Tierney excels both against the spread and straight-up. The past two seasons, he has hit on nearly 65 percent of his straight-up NFL office pool picks (330-180-2), beating the vast majority of experts on 

Tierney is an amazing 88-40 picking every game straight-up over the past nine weeks in a wild NFL season. Now, he has studied the matchups and locked in his optimal Week 13 NFL Survivor Pool pick, in which you need to pick one team each week to win but cannot select the same team twice in a season. 

This week, we can tell you he's not going with the Seattle Seahawks, 10-point home favorites against the San Francisco 49ers

These two teams certainly appear to be heading in opposite directions with five weeks left in the regular season. Seattle is in the NFC playoff hunt with a 6-5 record and two straight wins. Meanwhile, San Francisco has lost eight of nine and has just two wins all year. 

But if the Niners can cut down on turnovers, they can compete with Seattle. They have a putrid minus-17 turnover differential - only the Buccaneers (-21) are worse and no other team is greater than minus-11. 

San Francisco has lost four straight on the road, but three of those were by a field goal or less. In terms of total defense, the Niners rank five spots higher than the Seahawks, and the teams average the same number of yards per game offensively. There are too many red flags to pick Seattle, Tierney says.

Instead, Tierney is revealing a confident pick that sets you up well in your pool without causing too much stress. The time to pick this team is right now, and he's sharing his play over at SportsLine. He's also naming backup teams in case you've used his optimal option. 

So which team is a must-back in your Week 13 survivor pool? Visit SportsLine now to see which team will survive and advance, all from the man who went 166-88-2 in straight-up office pool picks last season and 88-40 the past nine weeks.