Manny Machado, for now, is a member of the Baltimore Orioles, though if the increasing frequency of trade rumors are to be believed, that could change. With just one more year remaining on his contract before he reaches free agency, it seems more and more likely that Machado may spend 2018 in colors other than orange and black.
It's not difficult to see why contenders would be interested in adding a three-time All-Star who can provide elite defense at either third base or shortstop and will still only be 25 years old on Opening Day, but there's an important question they need to ask themselves: What is he? After all, his 2017 line of .259/.310/.471 was essentially league-average, his lowest since his first full season in 2013 -- and part of that is because he was nearly shockingly unimpressive away from Camden Yards. 
Should either fact concern interested buyers? Both? Let's investigate.
Machado, at home, was a star in 2017. He hit 22 of his 33 homers in Baltimore, along with a .288/.350/.544 line that comes out to a .373 wOBA. (Weighted On-Base Average, or wOBA, is just like regular OBP, except that it gives more credit for extra-base hits rather than treating each time on base equally.) A .373 wOBA is fantastic; it's well above the non-pitcher MLB average of .326, and it's basically the equivalent of George Springer (.376) or Edwin Encarnacion (.373).
Machado, on the road, was not strong in 2017. He hit just 11 of his 33 homers on the road, along with a .229/.268/.398 line that comes out to a .280 wOBA. That's about the same as Jose Iglesias (.283) and Billy Hamilton (.278).

It's not the largest gap in baseball, but it's pretty close. As you'd expect, most hitters have a slight home-field advantage; across the Majors in 2017, non-pitchers had a .333 wOBA at home, and .319 on the road. Looking at the 144 hitters who qualified for the batting average title, there was a +.008 wOBA advantage at home. Performing better at home isn't terribly surprising. It's just that Machado's place on this list was well above where most other hitters landed.
Biggest home vs. road batting performances, 2017 (wOBA)
+.170 Charlie Blackmon, Rockies
+.128 Eddie Rosario, Twins
+.127 Carlos Gonzalez, Rockies
+.105 Mark Reynolds, Rockies
+.098 Rougned Odor, Rangers
+.097 Manuel Margot, Padres
+.096 Eugenio Suarez, Reds
+.093 Machado, Orioles
+.090 Nomar Mazara, Rangers
+.086 Paul Goldschmidt, D-backs
Three of the first four names on that list are Rockies, unsurprisingly, making Machado one of the non-Coors hitters with the largest home/road splits in 2017.

But why? Part of it was plate discipline, because Machado struck out more on the road (19 percent compared to 14.4 percent at home) and walked less (5.4 percent to 9.0 percent). Part of it is that he hit more grounders on the road, 45 percent of his batted balls, as compared to just under 40 percent at home, and part of it was that all the Orioles did better at home, with a .333 wOBA at home against a .305 away. Camden Yards, obviously, is a nice place to hit.
Part of it, however, was some unfortunate batted-ball outcomes. Machado's hard-hit percentage, or percent of batted balls over 95 mph, was 48.2 percent at home, and 47.2 percent on the road. It's not that different. It didn't help that more were hit on the ground outside of Maryland, so that's part of it, but consider his home/road differences in actual outcomes compared to expected outcomes.
Let's keep it simple and look at Expected Batting Average, which merely looks at the exit velocity and launch angle of each batted ball and gives the hitter credit on what usually happens, rather than what did happen. (This is important because if a hitter squares up a ball that's almost always a hit, but gets robbed of it because an outfielder happened to make an unbelievable play, we still want to credit the hitter for the skill displayed in hitting the ball that hard and far.)
Machado, at home, had a .349 Expected Batting Average, or xBA, on balls in play, and an actual average of .343. There's just about no difference there. He essentially earned what he got. On the road, he had an Expected Average of .322 … and an actual average on balls in play of .288. That's 34 points of value that he potentially earned and didn't get, either because of poor luck or good positioning or anything else.
Here, for example, Cameron Maybin robs him of a hit that falls for a hit 77 percent of the time.

Or consider the 409-foot out, with a 61 percent Hit Probability, that Zack Granite robbed him in July.

The good news is that "hitting better or worse at home" isn't really a repeatable skill, and for Machado, it's been inconsistent. He was average on the road in 2013 (.324 wOBA), poor in both '14 (.283) and '17 (.280), and very good in both '15 (.351) and '16 (.361). Meanwhile, at home, he's been a very consistent hitter over the last four years, always putting up a wOBA between .371 and .389.
Still, for his career, that adds up. Machado has hit .288/.341/.516 (.365 wOBA) in 382 games in Baltimore, and .271/.317/.438 (.323 wOBA) in an identical 382 games on the road. It's the difference between Corey Seager (.364 wOBA in 2017) and Denard Span (.325). It's not something that prevents you from acquiring the player, because Machado has shown, as he did in '15 and '16, that hitting on the road isn't a problem, but it does make you at least adjust for the fact that Camden Yards is very hitter-friendly.
There's also this: For all the talk about Aaron Judge and Giancarlo Stanton being the kings of crushing baseballs, no one had more hard-hit balls in 2017 than Machado's 250. This is exactly what we used in July to point out that despite Machado's disappointing first half (.230/.296/.445, .312 wOBA), he was still hitting the ball hard enough to expect a second-half rebound -- which he did, hitting .290/.326/.500, a .345 wOBA.
Machado had 130 of those hard-hit balls at home, and 120 on the road. He's a better hitter in the home whites, as most are, and an inconsistent one in the road grays. It's not something teams should worry about. It's something they should think about.