I guess it depends on what metrics you trust. If you look at raw OPS, then he looks closer to the player he was on the road in Colorado. If you use a stat that’s adjusted to both ballpark effects and league run environment such as wRC+, then Arenado has currently performed somewhere in between his previous home/road splits. Away Stats in Colorado 2255 PA / .793 OPS / 108 wRC+ Home Stats in Colorado 2303 PA / .985 OPS / 128 wRC+ St. Louis Cardinals 281 PA / .809 OPS / 120 wRC+ Arenado’s overall wRC+ with the Rockies (both home and road combined) was 118. So nearly identical to what he’s been in St. Louis so far. There has been research done on this previously by Mike Petriello and Jeff Sullivan. Sullivan found that the previous Rockies player home/road splits were less indicative of what to expect going forward than a player’s overall wRC+ (counting both home and road stats). Petriello found that with his test cases (Matt Holliday, Dexter Fowler, Seth Smith, Chris Iannetta, Clint Barmes) their decrease in home production with their new team was offset by their increase in road production. Here’s Petriello’s summary in his own words: This is why you can't just take the road stats for a Colorado player and project them across an entire season -- because a Rockies hitter is likely to do better on the road once he's not calling Denver home, as nonsensical as that sounds. Put it this way: they'll lose their home-field advantage, but they won't be at as much of a disadvantage elsewhere. Let's take one more approach, this time turning to OPS+, which accounts for park effects and is set so that 100 is "league average." How did this group do after leaving Colorado? Every single one improved, except for Barmes, who basically hit at his established averages no matter where he was. While five players is admittedly not a huge sample, there's no evidence that a Rockies hitter who goes elsewhere and gets regular playing time is going to fall apart. Back to Ryan McMahon, his sample size for 2021 is admittedly pretty small, especially when you cut it in half for home/road splits. His overall wRC+ this season is 106 (home wRC+ is 111; road wRC+ is 99). As that suggests I would expect him to be a slightly better than league average hitter overall (~105), although the lack of previous track record is certainly a good reason to proceed with caution. Barely above league average production doesn’t even sound that enticing until you consider the Brewers have a league worst 60 wRC+ combined from their third baseman this year. I guess if Wong stays healthy maybe the plan to have Urias cover 3B for the remainder of the season is enough. I do agree with those that have concerns about the acquisition cost for McMahon, the Rockies will likely want a package beyond what you’d expect a league average corner infielder with 2.5 years of control remaining to command.