When the Astros acquired Zack Greinke at the Trade Deadline, it gave Houston a 1-2-3 punch that rivals nearly any we’ve seen in the modern era. What went largely unnoticed was the impact the move had on the back end of the rotation, where Wade Miley now stands as Houston’s No. 4 starter.

Miley, whose one-year, $4.5 million deal with Houston also went largely unnoticed last offseason, had been the Astros’ No. 3 for the first four months of the season, helping the club to the best record in the American League and a healthy lead in the AL West.

Now, the left-hander is an integral part of Houston’s rotation, as well as a free agent at the end of the season who should have little trouble landing a multiyear deal on the open market.

“I saw him pitch in person a couple weeks back, and he was good,” a National League executive said. “Depending on the team, I see no reason he can’t perform as a No. 3 over the next couple of years; maybe a solid No. 4 on a top-tier club.”

About a half-dozen teams expressed interest in Miley last winter, but his criteria for choosing a team included two elements he valued over all others. And believe it or not, money wasn’t one of them.

Miley had so enjoyed his postseason experience with the Brewers in 2018, he knew he wanted to sign with a team he believed could play into October. He also wanted a straight one-year deal, while most of the clubs he and his agent, Tom O’Connell, were talking to wanted to include a club option for 2020.

“He did a great job betting on himself this year,” the NL executive said.

Miley’s half-season with Milwaukee in 2018 was a great success, a stark contrast to his brutal 2016-17 campaigns in Seattle and Baltimore, when he posted a 5.48 ERA in 62 starts. He had been forced to settle for a non-roster invitation to Brewers Spring Training, and after battling through a pair of freakish early-season injuries (groin, oblique), Miley had a superb three-month run, pitching to a 2.57 ERA in 16 starts for the season.

Milwaukee was 12-4 when he pitched, and after sweeping the Rockies in the NL Division Series, the Brewers went the distance with the Dodgers before falling in Game 7 of the NL Championship Series. Miley had a 1.23 ERA in four postseason starts -- one of which lasted one batter in the NLCS -- showing no fear under baseball's bright lights.

Given the Brewers’ wealth of young, controllable pitching entering 2019, a return to Milwaukee didn’t seem to be in the cards. Other teams made offers, but once the Astros got involved, it seemed like a matter of when, not if, he would sign there.

One offer he passed on was worth $2 million more than Houston’s $4.5 million guarantee (he’ll max out his incentives this season and earn another $500,000), but Miley’s history with manager AJ Hinch (they were in Arizona together earlier in Miley’s career) and his desire to play for a contender made it a no-brainer for the pitcher.

The decision has paid off for Miley, who is 13-4 with a 3.13 ERA, the fourth lowest in the AL. He’s allowed three or fewer earned runs in 25 of his 27 starts (he allowed four earned in the other two), including 17 outings with two or fewer.

More importantly, the Astros are 19-8 when he starts, giving the club he pitches for a 31-12 record in his games over the past two seasons.

“He took a one-year shot on himself, and he’s proven he has the durability,” an industry source said. “The trends from last year have continued. There’s no reason that teams shouldn’t want him.”

Miley’s turnaround coincided with his decision to refine his cutter, a pitch he used only 14.2 percent of the time in 2017. He threw the cutter 41.2 percent of the time in 2018, boosting that number to 46.2 percent this season. His changeup has also been a key factor, as he’s throwing it nearly twice as much this season (20.1 percent) as he did two years ago (10.8 percent).

“I really like the competitor,” the NL exec said. “He’s a strike-thrower, and he gets the ball going both ways with that cutter-changeup combo, which allows his fastball to play better.”

Skeptics question Miley’s peripheral numbers, specifically his 4.36 FIP in 2019 and 3.59 FIP last season, but the results have been inarguable. Soft contact is the norm against Miley, whose 87.1 mph average opponent exit velocity is 12th lowest in the AL this season (minimum 200 batted balls allowed).

“His ERA is better than his peripherals, but he’s done it two years running now,” one AL general manager said. “Is he someone that can continue to limit quality contact?”

Another AL executive believes his change in approach when it comes to pitch selection should enable him to do just that.

“He made smart changes with the Brewers last year,” the AL exec said. “He drastically increased the usage of his cutter -- his best pitch -- at the expense of his two-seamer, which was his least-effective pitch.”

The AL GM believes Miley could land a “Lance Lynn type of deal,” referring to the three-year, $30 million contract Lynn signed with the Rangers last offseason. Another AL talent evaluator wonders whether his age (32) will cause teams to hold the line at two years.

“His age is a factor, so I would see him more in the two-year-deal window,” the second exec said. “He is 24 months removed from being a non-roster invite, so I think generally people are leery to extend on guys like that.”

The three-year, $36 million deal J.A. Happ signed with the Blue Jays after the 2015 season is a good comparison for Miley, though Happ’s platform season (3.61 ERA in 172 innings, also at age 32) wasn’t as strong as the one Miley is having. To think Miley could land a Lynn-type deal or better is hardly going out on a limb.

Miley has induced more ground balls than all but three pitchers in the AL this season, while his ground-ball/fly-ball ratio ranks third in the league. Teams with strong infield defenses figure to be intrigued by Miley, who should be viewed in the second tier of free-agent starters with the likes of Zack Wheeler, Jake Odorizzi and Dallas Keuchel.

Should Gerrit Cole depart Houston as a free agent, Miley could be the obvious answer for the Astros. Greinke would slot into Cole’s spot as part of a 1-2 punch with Justin Verlander, while Miley would move back into the No. 3 role he filled for the first four months of this season.

“Lefties have traditionally aged well, but he’s not a hard-throwing pitcher, which is the prototype teams are looking for,” the industry source said. “But he’ll be in demand with the teams that are looking to compete. If teams are looking for effective starters to eat some innings, he’ll be on the higher end of the list.”