Mark Trumbo isn’t doing much cleaning up

It’s impossible to look at the numbers and not draw a correlation between Mark Trumbo’s extended slump and the added pressure he may have felt when he became the Angels’ full-time cleanup hitter July 17.

Trumbo, who had hit cleanup only against left-handers to that point, had two hits, including a homer, and three runs batted in at Detroit that night, pushing his season average to .311, his on-base percentage to .361 and his slugging percentage to .634.

He had 26 homers and 65 RBIs, 69 strikeouts and 23 walks, the free passes and OBP indications his plate discipline had improved drastically since 2011, when he hit .254 with a .291 OBP, 29 homers, 87 RBIs and 25 walks all season.

But in 37 games since July 18, Trumbo had hit .203 with a .263 OBP, .287 slugging percentage, four homers, no doubles, 15 RBIs, 52 strikeouts and 10 walks, including an 0-for-13 stretch entering Thursday. He was dropped to the fifth spot against right-handers Aug. 13.

“I hit fourth a little bit last year, and I was always a cleanup hitter in the minor leagues, so I guess I’m used to it,” Trumbo said. “Maybe not at this level, but an at-bat is an at-bat, and once you’re past that first go-round through the lineup, your spot comes up when it comes up.

“I don’t want to say it’s bound to happen, but there’s never been a season where I haven’t had a rough patch. It’s more of an extended period this year, but I’ve strung together some hits here and there.”

Trumbo appeared to break out of his funk last week in Fenway Park when he rifled a single to center in his first at-bat Aug. 21 and crushed a 440-foot homer over the Green Monster in the fifth inning. He had key run-scoring singles the next two nights to help the Angels sweep the series.

But he cooled off in Detroit last weekend and entered Thursday batting .277 for the season with a .330 OBP, .524 slugging, 30 homers and 80 RBIs. He has struck out at least twice in 15 of his last 26 games.

“The natural thought process is to try to fix whatever is causing it, which is mechanical stuff,” Trumbo said. “You grind on that for a while. Maybe it’s this, it could be that. You get a lot of people come to you and say, ‘Hey man, this is what I see.’ So you filter through that for a while.

“Then at a certain point you decide to give it up. I’ll have one at-bat where I’ll go deep in the count and have a different feeling, even if it doesn’t result in a hit. Usually that allows me to say, ‘OK, there it is.’ That’s usually how it works for me.”

September promotions

With rosters expanding Saturday, the Angels are expected to recall pitchers Nick Maronde from double-A Arkansas and Andrew Taylor from triple-A Salt Lake. Both are hard-throwing left-handers with sliders and changeups who could ease the loss of veteran left-hander Scott Downs, who is on the bereavement list.

The Angels are also expected to recall triple-A catchers Hank Conger and John Hester and infielder Andrew Romine either Saturday or early next week, when Salt Lake’s season ends. They will also activate outfielder Peter Bourjos from the disabled list after his triple-A rehabilitation stint.

mike.digiovanna@latimes.com