Mike Tomlin has declared that all established starters will sit Thursday night in the Steelers preseason finale vs. Carolina.

#Steelers established starters won't play vs. Panthers in preseason finale http://t.co/jYYce5PuBo pic.twitter.com/k3S4XHOeUM

— BTSC Steelers (@btsteelcurtain) September 1, 2015

This is standard operating procedure during the Mike Tomlin era and, given season ending injuries the Steelers suffered to Shaun Suisham, Garrett Hartley and Maurkice Pouncey, Tomlin’s policy appears all the more prudent.

• But Mike Tomlin is making a mistake.

Instead, Mike Tomlin should be sending a message. The Steelers starting defense should play defense vs. Carolina Thursday night. Every healthy established starter should be required to suit up and play this final preseason game. Tomlin’s message to them should be simple:

• You earn your rest for the final preseason game. Force a punt or secure a turnover, and sit. Let them score and continue to play.

There is precedent for this. In the penultimate game of the 2008 Steelers season, the Steelers traveled to Tennessee and lost badly. The team appeared unfocused. Mike Tomlin defined conventional wisdom and played his starters in the Steelers 2008 season finale vs. Cleveland, claiming he wanted to rid the team of the bad taste of losing before entering the playoffs.

• The 2008 Steelers playoff run of course ended in triumph in Super Bowl XLIII.

Not that Tomlin’s strategy didn’t carry real risks. In fact, the Steelers came close to paying a very hefty price when Ben Roethlisberger was injured with what the Pittsburgh Post Gazette labeled a spinal concussion. Had the 2015 NFL concussion protocols been in place, Bryon Leftwich might have ended up starting the Steelers playoff game vs. San Diego.

But the Steelers defense was bad vs. the Buffalo Bills. Very bad. While the unit clearly has talent to perform better, the defense is struggling. Worse yet, the performance was lack luster. Tomlin himself described his players as “the walking dead.”

Yes, taken in context, Tomlin’s critique was directed at the younger players supposedly struggling to earn their place in the NFL. Fair enough. But the Steelers first string defense gave up touchdown passes on the opening drives vs. the Packers and the Bills and, quite frankly, both teams made it look easy. This is a cycle which Mike Tomlin and Keith Butler must break.

The 2014 Steelers defense struggled during much of the year as the offense emerged as a dominant unit in the NFL. But during the final four games of 2014, the defense improved and that improvement drove the Steelers 4-0 finish. Mike Tomlin coaxed this improvement out of his defense opening the competition for roster spots and playing time.

• Tomlin should have applied the same philosophy to the Steelers preseason finale vs Carolina.

The 2015 Steelers defense might already have “established starters” but the number of proven starters on defense is far more finite. They are Cameron Heyward, Steve McLendon, Lawrence Timmons and William Gay.

Ryan Shazier, Jarvis Jones, Arthur Moats, Michael Mitchell, Shamarko Thomas, Cortez Allen, and Stephon Tuitt still have a lot to prove. If these men are healthy, Mike Tomlin should have them suit up and prove they belong.

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