The August 15 edition of MLB Immaculate Grid requires participants to name players who have donned the jerseys of both the Texas Rangers and Baltimore Orioles.
Hanser Alberto is a good answer. He was with the Rangers from 2015 to 2018. He also spent two seasons with the Baltimore Orioles (2019 and 2020). At the time of writing, just 0.3% of players had selected Alberto, so it's a very rare answer.

MLB Immaculate Grid answers August 15: Which other Rangers players have also played for the Orioles?
Here are some other options for the prompt:
- Harold Baines (1993-2000 with BAL, 1989-1990 with TEX)
- Chris Davis (2011-2020 with BAL, 2008-2011 with TEX)
- Kyle Gibson (2020-2021 with TEX, currently with BAL
- Vladimir Guerrero Sr. (2011 with BAL, 2010 with TEX)
- Rougned Odor (2014-2020 with TEX, 2022 with BAL)
- Sammy Sosa (1989-2007 with TEX, 2005 with BAL)
Nelson Cruz is another valid answer. He played for the Nationals, Padres, Orioles, Mariners, Rangers and Rays among other teams.

Be sure to visit Baseball Reference for more answers. They have a database that tells you every single player that's suited up for the Rangers and Orioles, which can help give you the rarest answer for today.