DETROIT -- The Tigers lost to the Phillies, 3-2, in a 15-inning game that began Tuesday night and ended early Wednesday morning. The unique circumstances of the defeat were secondary in importance to what sources say is likely to transpire with the franchise in the coming days.

• The Tigers are virtually certain to trade Nicholas Castellanos, who crushes left-handed pitching and is due to become a free agent after this year.

• The Tigers probably will trade closer Shane Greene, too. He pitched a scoreless inning Tuesday before scouts from the Dodgers and Nationals, two teams known to have interest in him. One source said Tuesday that the Tigers recently have become more active in discussions about moving Greene.

• And the Tigers remain uncertain about whether they will trade left-hander Matthew Boyd, who turned in a quality start Tuesday (six innings, two earned runs) in his final home outing before next Wednesday’s Trade Deadline.

In discussions with various teams, the Tigers have proposed the possibility of pairing Boyd and Castellanos -- or Boyd and Greene -- in the same trade, as a way to access the highest tier of available prospects. It’s not necessarily the case that the Tigers will insist on position player prospects in trades, even though their system is stronger among pitchers.

Here’s an update on the Tigers’ principal trade candidates, with one week of midseason shopping left across the Majors.

Boyd: Tuesday’s game marked the first time since May 28 that Boyd surrendered two or fewer runs in a start -- a welcome sight for a Tigers front office that maintained a high asking price on the 28-year-old despite a 6.08 ERA over his preceding eight starts.

One National League executive said Tuesday the Tigers’ prospect requests for Boyd have been so high that some in the industry doubt that he will be moved at this year’s Deadline. After all, the Tigers control him through 2022, by which time they expect to have a competitive team.

Boyd has surrendered 15 home runs in his last nine starts, but he also ranks sixth in the Majors this season with 168 strikeouts.

The Yankees were among the teams with a scout in attendance at Boyd’s start on Tuesday. The Phillies have spoken with the Tigers about Boyd and Greene, as first reported by Jim Salisbury of NBC Sports Philadelphia, and Philadelphia GM Matt Klentak was in attendance at Tuesday’s game.

The Tigers aren’t actively discussing Boyd with the Astros, and talks between the Tigers and Padres regarding Boyd failed to advance, sources say.

Castellanos: The 27-year-old right fielder told MLB.com over the weekend that the trajectory of his season changed last month, when he drove with his girlfriend and son on the Tigers’ road trip to Pittsburgh and Cleveland. Castellanos said the time with loved ones helped to clear his thoughts about the upcoming Trade Deadline and free agency.

The result? He has a .958 OPS over the past month.

A source confirmed a report by Chris McCosky of the Detroit News that the Cubs have spoken with the Tigers about Castellanos. He seems likely to wind up in the National League, because of his potential production against the Dodgers’ dominant left-handed pitching.

Castellanos grades out as a below-average defender in right field, but that would be less of a consideration in a ballpark with a smaller outfield area. Castellanos may be open to playing first or third base with a new team, as a way of contributing on a contender and improving his free-agent value.

Castellanos’ recent comments criticizing the spacious dimensions at Comerica Park have made his departure all the more certain.

Greene: Greene was a setup reliever as recently as two years ago, and it’s likely he would be comfortable with a return to that role as a Dodger, given Kenley Jansen’s presence there. The Dodgers prefer to acquire a left-hander (Felipe Vazquez or Will Smith) to pair with Jansen in the late innings, but Greene is high on their list among right-handers.

The Nationals view Greene as a strong complement to their left-handed closer, Sean Doolittle. The Braves also have scouted Greene, although the Tigers and Braves have yet to engage in serious talks regarding him.

Of note, Greene isn’t the only trade candidate in the Tigers’ bullpen. Right-hander Buck Farmer threw a perfect inning Tuesday, including strikeouts of Scott Kingery and Rhys Hoskins. Farmer, like Boyd, won’t be eligible for free agency until after the 2022 season, but the Tigers could seize upon the industry-wide need for bullpen help by trading the 28-year-old now.