The Oakland Athletics have acquired right-handed pitcher Dawrin Frias from the New York Mets as the player to be named in the Eric O'Flaherty trade. Frias (in Baseball Reference as "Darwin") is a 23 year old from the Dominican Republic signed by the Mets in 2009. This is his seventh season in minor league baseball, and he can become a free agent after this season.
Frias was actually playing for New York's Class-A Short Season team in Brooklyn and preparing to start against Oakland's corresponding team, the Vermont Lake Monsters, when the completion of the trade was announced:
Dawrin Frias, expected to start for BKLYN tonight, has been traded to Oakland and will report to Vermont, the team he was supposed to face.— Brooklyn Cyclones (@BKCyclones) August 7, 2015
The A's were really just trying to give away Eric O'Flaherty, and Frias is effectively the consideration necessary for the trade sending Eric O'Flaherty and cash to the Mets to not raise eyebrows in the Commissioner's Office. A return of cash for a trade that initially sent cash is frowned upon because that's not really a trade but giving money away. A player can have whatever value the teams deem them to have, however. As they say in contract law, when it comes to consideration, even a peppercorn will do.
You shouldn't care, but if you must: Frias started the year in the full season Class-A South Atlantic League, where he made 15 relief appearances totaling 20⅔ innings while striking out 22 and walking 16 with an 8.71 ERA. He was sent to Short-Season A and has made four appearances there, striking out 10 and walking four in eight innings, earning a 3.38 ERA.