It’s Chicago White Sox lefty Luis Avilan:

They needed another left reliever. That much I know.

I asked BWanks for his take:

“It makes sense. Each of the last two games Adam Morgan couldn’t get a big out against a LHH to keep the game within reach. Lefties are hitting .247 against Morgan this year, and he has allowed 11 of 34 inherited runners to score. Avilan, meanwhile, has a 10.4 K/9 mark and a 3.86 ERA, but his FIP is 2.70. He’s been a bit unlucky. Lefties are only hitting .214 off him this season. With guys like Freeman and Markakis in Atlanta and Soto and Harper on the Nats, they need a reliable dude that can get out left-handed hitters in big spots.”

Here are Avilan’s career numbers: