Trivino, Casilla on the rise

HOUSTON — Oakland’s bullpen is in flux, with injuries and underperformance, which means roles are changing. Among the intriguing recent developments: Rookie Lou Trivino and former closer

Santiago Casilla might see more action in the sixth or seventh innings, effectively moving past Emilio Pagan and

Chris Hatcher.

“He’s really done a nice job for us,” A’s manager Bob Melvin said before Sunday’s game of Casilla, who before a rough eighth inning Sunday had allowed only two hits in his previous seven appearances. “For a guy who’s used to pitching and pitching a lot in a certain part of the game, he’s had to acclimate to a different role, and he’s done it beautifully . ... If he has success,

it means we can tweak some things. We like where we are in the eighth and ninth innings right now, but something before that, potentially.”

Blake Trienen remains in the closer role, and the setup men are Yusmeiro Petit and

Ryan Dull. Hatcher, a former setup man, is no longer getting high-leverage situations after allowing eight earned runs in nine appearances. “We’re trying to give him a couple of different outings just to try to take the pressure off and figure some things out; he’s had some struggles,” Melvin said.

“He’s maybe not throwing as many strikes as he did, and certain parts of the zone he commanded before he’s having trouble with right now, but we feel like he’ll get that back.”

Another reliever on the rise: Trivino, who is unscored upon in four outings and who could see more late-game action. “When you throw 98 and the ball moves all over the place, if you throw it over the plate, you’re going to have success,” Melvin said. “It’s just the inexperience, but we think he has a really good career ahead of himself, and it looks to be starting now. We could see him the later part of the game, too.”

Pagan, who has allowed runs in eight of 12 outings this season, said that he believes he has spotted a flaw in his delivery: He’s back on his heels too much, causing him to fly open. That affects his release point and also allows hitters a better and longer look at the ball.

“I just need to throw better quality pitches, and with these adjustments, I think that will come,” he said.