Yes, you read that headline right. From Kurt Warner's (verified) Twitter account:
Woke up this morn[ing] and took kids to a Chiefs prac[tice] and then a visit to play some ball at Arrowhead stadium!
A new quarterback in town? I don't think so.
The connection here is likely Todd Haley. Warner and Haley were together in Arizona from 2007-2008.
Still, a bit strange to see a future Hall of Fame quarterback seemingly randomly visiting the Chiefs.
Warner may not have a great memory of Arrowhead. The first and only time he played there was with the Rams in 2000. If you'll recall, the Greatest Show on Turf got whooped 54-34.