"In Memory of Big K," it reads, in homage to the beloved right tackle who collapsed and died four years ago from heatstroke during a sweltering July day at camp.
Now the Vikings, and a few other NFL teams, are giving some of their players a pill that allows trainers to monitor their core temperature in hopes of never again having to create such a memorial.
The Core Temp Ingestible Core Body Temperature Sensor was developed in the late 1980s by HQ Inc., of Palmetto, Fla., as a research tool used for a number of projects, including monitoring how certain pharmaceutical drugs affect the body's core temperature.
In the past two years or so, according to marketing director Susan Smith, the product has evolved into a protective device for athletes in football, tennis, running and other sports who train in intense heat.
Without the pill, monitoring is anything but an exact science.
"We've had some people get to 106 degrees and not have symptoms and some get to 102 and have symptoms," said Rick Burkholder, head athletic trainer for the Eagles. "Some guys' core temperature rises after they come off the field and stand around, and other guys it goes down when they come out. It depends on the individual."
Such was the case in Mankato on July 31, 2001, with the 335-pound Stringer. The heat index soared to 110 degrees on that day, the hottest day of the year in Minnesota.
Stringer had left practice early the day before. Determined to stick this one out, he labored during his final practice, but didn't summon a trainer until the session was over.
Head coach Mike Tice, who was offensive line coach at the time, said Stringer never showed any symptoms of heat illness.