LOS ANGELES - With the A’s bullpen a bummer much of the season, could R.J. Alvarez now help turn things around? Alvarez had a tough time of it while with Oakland earlier in the year, allowing four homers in just nine innings. With Triple-A Nashville, though, the reliever allowed no homer runs in 24 innings and opposing right-handed hitters batted just .170 against him, making him a potential right-on-right specialist in key situations for the A’s. “Potentially,” manager Bob Melvin said.