What could it mean? Was he watching a particularly drama-filled episode of The Bachelor? Did he just see something shocking through his bedroom window? Did he poke himself in the eye?
Twitter came up with several theories on the meaning of Thomas's cryptic tweet, few of which had to do with the condition of his actual eyeballs.
According to Celtics assistant general manager Mike Zarren, within minutes of the tweet's appearance on the internet, he received inquiries from around 20 reporters on whether it meant a deal was coming before Thursday's 3 p.m. ET deadline.
Life in 2017: A player randomly tweets 👀 and ~20 reporters instantly txt or call you demanding to know when the trade is happening. Lol.
The apparent overreaction wasn't without reason, though. As Celtics reporter Jay King pointed out, the last time Thomas tweeted the same emoji, Al Horford announced he had signed with Boston shortly afterward.