This journey backward may turn your stomach green, but we must look back at the Detroit Lions’ 2012 season before we look forward.

 Got that?

  Belt yourself in. The trip back in time will be quick, but I can’t guarantee it will be painless.

  — Let’s start in Nashville on Sept. 23. No one thought the Tennessee Titans had a chance. We won’t even mention the Titans’ punt and kickoff touchdown returns. The Lions defense gave up three huge scoring plays — a 61-yard pass from Jake Locker to Jared Cook, a 71-yard touchdown pass from Locker to Nate Washington and in overtime the Titans drove 72 yards on 13 plays to score the game-winning 26-yard field goal. Detroit’s defense allowed 378 passing yards that day. Even though the Lions won the time of possession battle 40 minutes to 28, the defense couldn’t hold when it needed to the most. 

 — Let’s move ahead to Nov. 11 at Minnesota. The Metrodome is a tough place to play, but no excuses. The Lions’ defense gave up 403 net yards — 189 rushing, 171 of those by Adrian Peterson who had a 61-yard, fourth quarter touchdown scamper. The Lions’ defense knew they had to stop AP and yet they could not, even in the fourth quarter. Vikings won 34-24.

 — Now it’s time for the real turkey, the loss to the Houston Texans on Thanksgiving. There is plenty of blame to spread around on this loss. Jim Schwartz for the red flag penalty and Jason Hanson for a rare missed field goal come to mind. But the Lions defense gave up 505 yards in that 34-31 overtime loss. Houston’s Andre Johnson caught nine balls for 188 yards. 

— OK, one more. On Dec. 2 at Ford Field the Lions had a 33-28 lead over the Indianapolis Colts with three seconds left and then Andrew Luck threw a 14-yard, game-winning touchdown pass to Donnie Avery on a fourth-and-10. Detroit became the first team to lose three straight after holding the lead with two minutes remaining in regulation since the 2000 San Diego Chargers.

   Enough said.

  The Lions’ defensive woes were a huge reason why they finished the season a most disappointing 4-12.

 Once the dust settled, general manager Martin Mayhew said he wanted more impact players on defense. More difference makers.

  For all of the ugly reasons above, the defensive side of the ball cannot be overlooked when it comes to the NFL draft.

  At this point — free agency isn’t over yet — the defensive roster has less talent than last season.

 Defensive end Jason Jones was a good, reasonable free agent pickup, but he is no Cliff Avril who signed with the Seahawks.

  Kyle Vanden Bosch was cut and there is no clear answer to fill his spot at right defensive end. Willie Young and Lawrence Jackson are possibilities, but Jackson is not signed.

  Louis Delmas agreed to a two-year contract on Friday. Now he’ll play alongside durable safety Glover Quin who should provide stability in the backfield.

 Chris Houston is back which is huge. He’s the quiet leader who can really help along the three young corners who were drafted last April.

 Linebackers Stephen Tulloch and DeAndre Levy are back, but Justin Durant is gone.

  Young guys may be able to step up, but nothing is for certain yet.

  That why I say on April 25, the first night of the draft, the Lions should go for defense with the fifth overall pick.

  Because left tackle Jeff Backus retired, some folks think it’s a natural move to draft either of the top two rated offensive tackles — Eric Fisher (Stoney Creek, Central Michigan) or Luke Joeckel (Texas A&M).

  I disagree.

  At this moment the offensive line is in better shape than the defensive line.

  It’s not like there’s just one good defensive player in the top 5 or top 10.

  In the draft, the Lions could have their choice between a few defensive players: 

— Outside linebacker Jarvis Jones who excels at the pass rush and is projected to play a game similar to the Broncos’ Von Miller.

— Dee Milliner, a highly touted cornerback from Alabama.

— Defensive end Ziggy Ansah (Brigham Young) who has slowly crept up the draft boards. Mel Kiper has the Lions drafting Ansah in his March 11 mock draft.

 — Outside linebacker Dion Jordan (Oregon) will likely be available but he might fit a 3-4 scheme the best.

   Detroit needs defensive depth from the later rounds too.

  Trust me, the Lions are not going to trade up. Several mock drafts have Joeckel and Fisher going in the top three.

 Trust me on this too. If the Lions’ defense is not upgraded through free agency and the draft, it doesn’t matter how much of a difference that Reggie Bush will make for the offense. Unless he can play defensive back too.

  (For continuing coverage on Lions free agency, follow @PaulaPasche on Twitter. Also check out oplions.blogspot.com and TheOaklandPress.com.)