If you blink, you’ll miss it, but Chase Utley shows up in the Always Sunny season 16 trailer right around the 51-second mark:

Rob McElhenney teased this a few months ago, when he posted a tweet showing on-set trailers, one of which featured Utley’s name.

Utley has been on IASIP before, notably in that episode where Dennis and Charlie crash a charity event with Chase and Ryan Howard in attendance. There’s also the scene where Mac writes Chase a love letter, which has got to be one of the top five or top 10 most famous clips from the show. Eventually Utley and McElhenney became friends, and Chase has thrown out a couple of pitches to him at Phillies games, first in 2019 and then again during the 2022 World Series.