Jay Glazer reported on the Fox pregame show that McCoy was deactivated to make room for another defensive lineman on the active roster.
McCoy joined quarterback Chad Henne, offensive linemen Jackson Barton, Andrew Wylie and Ryan Hunter, linebacker Darron Lee and cornerback Morris Claiborne on the inactives list.
Ian Rapoport of NFL.com added that McCoy was a healthy scratch:
Ian Rapoport @RapSheet
The Super Bowl LIV @NFLGameDay Notebook with @MikeGarafolo: -- The inactive list is out and #Chiefs RB LeSean McCoy is on it. A healthy scratch. CB Morris Claiborne is also inactive. -- The planned Kobe tribute has the players lining up pre-game on the 24-yard line. https://t.co/n4Z4YDlPTe
The move doesn't come as a major surprise. As Josh Alper of Pro Football Talk noted, McCoy has been inactive for three of the team's past four games, and only played one snap in the team's divisional-round win over the Houston Texans.
Damien Williams, Darwin Thompson and Anthony Sherman are all active, meanwhile. Williams has been the team's main option in the postseason, rushing 29 times for 92 yards and three scores. He's also caught seven passes for 65 yards and another score in the playoffs.
McCoy, meanwhile, had his worst season as a pro, rushing for just 465 yards (a career low) and four touchdowns. He did average 4.6 yards per carry but fell down the rotation behind Williams and Thompson.
As for the Chiefs, the move will allow them to have some more depth in the front seven and more bodies to rotate into the game. Keeping the team's defensive lineman will be key against a San Francisco rushing attack averaging an incredible 235.5 yards per game on the ground during the postseason.