And Mychal, the family patriarch, was the No. 1 overall pick in the 1978 NBA Draft and won back-to-back championships with the Lakers in 1987-88. It was Klay and Mychel who tweeted out jubilant messages of their brother's big league arrival over the weekend, even without Trayce telling them directly and before the news became official.
"I don't have social media or anything, so it didn't even cross my mind to let them know to kind of keep their mouths shut," said a smiling Thompson, after he was called up from Triple-A Charlotte to replace right-hander Scott Carroll on the roster. "I really didn't even tell them. I called my dad, and my dad has a fat mouth, so he told them.
"Then they're probably the two worst people to get it out to because they have so many followers and stuff. It's a tough situation, but I'm just glad I'm here, and they'll be here tonight, so it's going to be fun."
Thompson posted a .260 average this season for the Knights with 23 doubles, four triples, 13 home runs, 39 RBIs, 53 runs scored, 23 walks and 11 stolen bases over 104 games. He has appeared in 94 games in center field, five in right and four in left. He is ranked by MLBPipeline.com as the club's No. 15 prospect.
This promotion stands as the culmination of seven years' worth of hard work and perseverance, after Thompson was selected in the second round of the 2009 Draft. He could get a start at some point in the Rays series.
"Athletic kid, smart baseball player," said White Sox manager Robin Ventura of Thompson. "With [J.B.] Shuckie going down [with a left hamstring strain], we kept Scotty an extra day and that seemed to work out yesterday when we needed him. But we need that extra outfielder and Trayce was playing the best at that time."
Tyler Saladino and Carlos Sanchez, who also were promoted from Charlotte this season, were part of Monday's starting lineup for the White Sox. Thompson becomes the ninth player this season to go from the Knights to the White Sox, with Thompson and Saladino actually splitting a two-bedroom place in Charlotte.
That apartment is available for sublet, with Saladino, Thompson and his family in Chicago.
"They're so proud, and I couldn't be here without them," said Thompson, whose mother, Julie, also was in Chicago. "They played with me growing up.
"Even last fall, during the World Series -- being in San Francisco -- we went and played Wiffle ball. They still love the game, so it's been a lot of fun."