Jorge L. Ortiz

USA TODAY Sports

OAKLAND – Jeff Luhnow is perfectly aware of the high price of upgrading at this time of year.

The Astros general manager saw Daniel Mengden, a Class A pitcher in Houston’s farm system a year ago, start against his club for the Oakland Athletics on Wednesday. Three other young players traded to boost last season’s playoff push – Brett Phillips, Josh Hader and Jacob Nottingham – are now among the Milwaukee Brewers’ top 10 prospects.

Moreover, the haul from last July’s trades – Carlos Gomez, Mike Fiers and Scott Kazmir – did not exactly pan out as expected, and the offseason deal for reliever Ken Giles hasn’t either.

But with the Astros trimming their deficit in the American League West from 10 games to 3½ in three weeks, Luhnow is back looking for those key elements that may help them return to the postseason after ending a nine-year drought last October.

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As much as it might pain Luhnow to part with prospects who may someday come back and beat his club, it’s still preferable to be trying to augment for the stretch run than to discard veterans after falling out of the race.

“If you’re in a position to make the playoffs, you feel a responsibility to the players, to the organization, to the fans, to do whatever you can as a general manager to put the team in the best position,’’ Luhnow said. “Having said that, you always have to be cognizant of what you’re giving up and how it’s going to hurt you in the future, and we gave up some really good prospects last year.’’

Not so many that the Astros, who built up their system through several years of high draft picks plus some shrewd scouting and maneuvering, have run out of coveted trade chips.

In fact, Class AAA shortstop Alex Bregman, taken second overall in the 2015 draft, is regarded in some parts as the top player still in the minors, although he’s essentially untouchable and may be called up as a multi-position player to help out in the playoff drive.

That option was made possible by Houston’s recovery from a 7-17 April, fueled by the all-around brilliance of second baseman Jose Altuve, shortstop Carlos Correa’s RBI tear – he has a major league-high 29 since June 20 – and a turnaround by a pitching staff that sported an unsightly 4.97 ERA in the first month of the season.

It has been 3.43 since then, with surprise All-Star Will Harris and unsung heroes Chris Devenski and Scott Feldman buoying a bullpen that boasts the AL’s second-best ERA (3.12) and is holding opponents to a .234 batting average.

But even though the injury-ravaged Texas Rangers have been faltering – going 4-12 with a 7.21 ERA in July and recently putting Prince Fielder and Shin-Soo Choo on the disabled list – the Astros might need help to overtake them in first place, especially considering Houston has gone 1-9 against Texas.

The most obvious spot appears to be the rotation, where Doug Fister (10-6, 3.42 ERA) has been the most consistent performer. Even if starters Dallas Keuchel and Collin McHugh continue to bounce back from their rough first two months, the back end could use a boost.

Plus, Luhnow realizes that Houston’s .680 clip (34-16) since May 24 might not be sustainable.

“We’re going to have our bumps somewhere along the road,’’ he said. “Hopefully we have built up enough wins and we have enough options of players that we’ll be able to withstand any bumps that come.’’

One of those options figures to be Cuban infielder Yulieski Gourriel, signed last week to a five-year, $47.5 million contract. The Astros are counting on Gurriel, a veteran of international amateur ball and most recently the Japanese league, to make a quick transition to American baseball and to contribute at the major league level as soon as August.

He would probably take over at third base, where Luis Valbuena has provided solid production with 12 home runs and an .812 on-base plus slugging percentage. Gourriel’s presence may force Valbuena to move to first in a platoon with Marwin Gonzalez, a fellow unheralded veteran who is part of the fabric of the team.

Valbuena says all the right things about the addition of Gourriel – “When he gets here, he’ll be welcome. We’ll make him feel at home.’’ – but manager A.J. Hinch acknowledges such late-season moves require adjustments that may be difficult.

The youthful Astros incorporated established players like Gomez, Kazmir and Fiers last July and managed to claw their way to the playoffs, even with the first two playing below expectations.

Whether it’s Gourriel or other frontline players the club brings in, the Astros are in for some changes just as they pursue a playoff berth.

“Something like that is going to cost somebody their job, and that hits a clubhouse hard,’’ Hinch said. “I don’t care if you’re the 25th man on this team or a primary player who ends up getting traded, any time you change the mixture, like any good family, like any good group together, it’s going to have an impact. We’re strong enough to handle any of the change or any personality that enters our clubhouse. We have that good a chemistry. But it will be a test over time to see how it truly impacts us.’’

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