HEADING HOME — Chicago catcher Wilson Contreras tags out David Freese on Tuesday. (AP Photo)

PITTSBURGH — Jameson Taillon spent the hours before the trade deadline doing some detective work. The Pittsburgh Pirates pitcher scoured Twitter for updates, asked team trainers if they were scanning medical records and touched base with acquaintances of potential targets for a brief rundown on who might be joining the hottest team in the majors.

“I had fun with it,” Taillon said. “My heart was racing, I think.”

So are the Pirates.

Hours after his team picked up Texas closer Keone Kela and Tampa Bay starting pitcher Chris Archer in an effort to give Pittsburgh’s surprising postseason push a jolt, Taillon pitched effectively into the seventh inning and the Pirates held on late for a 5-4 victory over the Chicago Cubs on Tuesday night.

“We’re really excited for the additions,” Taillon said. “I think we still kind of don’t have anything to lose so we’re going to keep playing free. Going to hopefully play complete games like we’ve been doing and see what we can make happen.”

Gregory Polanco hit his team-leading 19th home run, a solo shot in the eighth that gave the Pirates a two-run cushion. They needed it after closer Felipe Vazquez gave up a single to pinch-hitter David Bote leading off the top of the ninth and Addison Russell followed with a shot to the gap in right-center that scored Bote.

Russell sped to third on the play and was initially ruled safe , but the call was overturned upon review. Vazquez retired the next two batters to pick up his 24th save in 28 opportunities.

“I’d like to see the replay on that last play, because I didn’t see it,” Cubs manager Joe Maddon said. “I went up and looked at it. The call on the field has integrity and I’d really need to see why that was changed.”

David Freese added a pair of RBI doubles for the Pirates, including a drive to the gap in right-center in the fifth that scored Polanco and put Pittsburgh ahead to stay as the resurgent Pirates won for the 16th time in 20 games.

“We’ve been fighting the last month,” Polanco said. “We know we want to play in October and to bring in pitchers (like Kela and Archer) is good for us and you know, that’s a good plan. You’ve got to keep fighting, keep winning.”

Taillon (8-8) allowed three runs on seven hits in 6 2/3 innings of work, his lone mistake an off-speed pitch to Javy Baez in the fourth that Baez turned into a three-run homer that tied the game.

Baez finished 3 for 4, including his shot to the rotunda behind the left-field seats that boosted his season home run total to 22, but the Cubs hit into two double plays and left seven runners on base to lose for the third time in four games.

Jon Lester (12-4) hadn’t lost on the road since falling to Cleveland on April 25. He needed 101 pitches to labor through five innings, giving up four runs on seven hits with three walks and three strikeouts. Lester is 2-1 with a 4.69 ERA in four starts against the Pirates this season.

“It seems like every time I throw against them, I’m not getting ahead,” he said. “Kind of a grinder. Hopefully, I get another shot. I feel like I haven’t pitched even close to anything good against these guys.”

The Pirates were reeling three weeks ago but have moved into the playoff chase by posting the best record in the majors since July 8. General manager Neal Huntington splurged at the deadline, bringing in Archer and Kela while parting with young prospects in outfielder Austin Meadows and pitchers Tyler Glasnow and Taylor Hearn.

Huntington called the decision a difficult one but felt it was worth it with both Archer and Kela under team control through at least 2020. Either way, the Pirates enter August in the thick of a crowded NL playoff chase. Consider the Cubs believers in Pittsburgh’s chances after their NL Central rival drew within six games of first place.

“I think this team is definitely not out of it,” Lester said. “I think we’ve seen in the past where they do get maybe a little bit on the streaky side. Hopefully, you kind of catch them when they’re not streaking in a positive way. But yeah, their offense gets rolling. They’ve got a good group over there.”

TRAINER’S ROOM

Cubs: RHP Yu Darvish (right triceps) reported no pain following a bullpen session on Tuesday. Darvish, who hasn’t pitched since May 20, called it a “starting point” and remains out indefinitely. The four-time All Star also brushed off comments made by former MLB star-turned-ESPN analyst Alex Rodriguez, who said during a broadcast on Sunday night that Darvish’s slow rehab was a distraction in the Chicago clubhouse. Darvish said “it doesn’t matter” what Rodriguez thinks of him.

UP NEXT

Cubs: Cole Hamels will make his first start for the Cubs on Wednesday when the teams wrap up their two-game set. Chicago acquired Hamels from Texas last week. The four-time All-Star went 5-9 with a 4.72 ERA for the Rangers this season.

Pirates: Nick Kingham (5-5, 4.80 ERA) will try to bounce back after giving up six runs in three-plus innings in a loss to the New York Mets last Thursday.