By Kay Lazar Globe Staff

Most people watching tonight’s Red Sox game at Fenway Park probably will focus on the competition with the visiting White Sox and former teammate Kevin Youkilis.

But there is another rivalry brewing.

Executives from the Red Sox front office are slated to announce their “step” challenge against another corporate giant -- Blue Cross Blue Shield of Massachusetts -- in an on-field presentation before tonight’s game.

The event is intended to highlight an ambitious campaign launced by the city in April, dubbed Boston Moves for Health, which encourages Bostonians to shed a collective 1 million pounds over the next year. The call to action includes a challenge for residents to walk 10 million miles altogether during the year-long campaign.

The Red Sox vs. Blue Cross Challenge will pit roughly 20 executives from each organization against each other in a competition to see which team can walk the most steps between July 23 and Aug. 13, according to the Boston Public Health Commission, which is organizing the event.

The executives will wear pedometers to track their steps, and log their activity on the Boston Moves for Health website, according to commission spokesman Nick Martin.

“Both companies happened to be holding internal step competitions this spring/early summer, but we’re really excited to have two of our high-profile Boston Moves sponsors competing with one another to raise awareness about physical activity and exercise,” Martin said.

The campaign could use some help. The website shows that as of mid-day today, nearly 2,700 registered participants have collectively lost just under 9,000 pounds, and logged just about 13,300 miles.