In exchange, the Angels received right-handed pitching prospect Erik Manoah.
Salas will add depth to a Mets' relief pitching staff that already ranks among the best in the Majors. Anchored by closer Jeurys Familia, Mets' relief corps have posted a 4.4 fWAR this season, good for fifth in the Majors. Their ERA of 3.68 ranks eleventh.
The 31-year-old Salas is 3-6 with a 4.47 ERA and a 45-to-19 strikeout-to-walk ratio in 56.1 innings pitched this season. He has a 4.64 FIP and a 4.50 xFIP, as well as a -0.2 fWAR.
The Mets, however, are buying stock in the recent version of Salas.
Over his last 20 appearances, Salas has a 2.60 ERA and a much improved 18-7 strikeout-to-walk ratio in 17.1 innings. He has been serving as the Angels' closer recently, and he has saved four games in August alone.
Salas was arbitration eligible for the final time last offseason, meaning he will be a free agent at the end of the year. The Mets are adding him for a possible playoff run, where his back-end relief experience should come in good handy.
As for the Angels, a move of Salas, who is a rental, makes sense for a non-contending team.
In return, they got Manoah, who was the Mets' 13th round pick in the 2014 MLB Draft. This season, in Class-A Short Season Brooklyn, Manoah is 5-5 with a 5.37 ERA and a 63-27 strikeout-to-walk ratio in 62 innings (13 games; 12 starts).