Katie Camlin tweeted Monday afternoon that a Chiefs front office employee came to Plaza Liquor and bought six bottles of Dom Perignon champagne.
Camlin later deleted the tweet before news broke that the Chiefs had signed Mahomes to a 10-year contract extension worth up to $503 million.
"Off the cuff, I tweeted it because I'm a Chiefs fan and I was beyond excited," Camlin told USA Today.
"It's kind of fun to have a scoop."
Camlin said she deleted her tweet because she didn't want to get in trouble at work or lose business for the liquor store.
Mahomes is now signed with the Chiefs through 2031. His extension includes a $140 million injury guarantee and a no-trade clause. Mahomes was already under contract for the next two seasons.
NFL training camps are scheduled to open in late July amid the coronavirus pandemic. Team facilities remain closed to players unless they need medical treatment. The NFL preseason has been shortened from four to two games. The NFL players' union has recommended for the league to cancel all preseason games.