The most elusive and valuable asset in all of sports is pace. You can't teach it and it's rare to find. Orlando City is not a particularly fast team, and Major League Soccer, as a league, isn't particularly fast. There is one extreme exception, however, and his name is Ruan.
Ruan is such a unique player on Orlando City's roster. The Brazilian right back is not only fast, he's probably the fastest player in all of MLS. That legitimately elite speed is usually an asset offensively, but he also has the recovery pace defensively that allows him to play basically as a winger when Orlando has the ball.
Nobody on the Orlando City roster does what Ruan does. Nobody on the Orlando City roster can do what Ruan does. And that makes him genuinely un-replaceable.
There are more valuable players on the team, and other players will be more influential for Orlando's season. Ruan's backup, Kyle Smith, is a perfectly serviceable MLS player and the pair of homegrown right backs, Michael Halliday and Alex Freeman, could potentially do a job at that spot. But nobody opens up the game the way Ruan does.
With Ruan in the team, the long ball on the right is always an option. Mauricio Pereyra can drop a long pass in behind and Ruan's pace allows him to test the defense. His vertical pace down the right flank allows Facundo Torres to cut in and have more fluidity in his positioning. And again, the recovery pace protects the Lions in transition, even if Ruan isn't the sharpest defender around.
If Orlando is going to operate at top capacity, it needs some semblance of true pace out wide to stretch the backline. Playing primarily with inverted wingers, that requires the fullbacks to overlap. That's not Joao Moutinho's role, and it's not in Kyle Smith's wheelhouse. Ruan is the only natural wide threat and his pace makes him un-replaceable. For an elite 2021 season, Orlando needs a career season from its Brazilian right back.