Fans only get to see the on-pitch Rosales on matchday, and before the Dallas game a small smattering on the Southsiders forum questioned just how much of a benefit it was bringing a player of his age and on his salary to the club at this late stage of the season, especially when the team was crying out for a proven goalscorer.
Now without sounding like a broken record, it’s the work that he does away from the actual game that is why he’s so important to the Whitecaps right now. He’s been working hard with the ‘Caps group of young strikers to help them see the game in a different way and to raise their own skill and workrate.
You can see some results. They’re maybe not earthshattering just yet, but they are there and there has been some noticeable improvements.
He initially did a lot of work with Kekuta Manneh and in recent weeks he’s been spending a lot of time working on his link up play with Erik Hurtado and Sebastian Fernandez, as that pair established themselves as Vancouver’s go-to front two.
Fernandez grabbed his first two goals for 14 games on Saturday, both assisted by Rosales, and there could have been more. After the game, the Uruguayan told reporters, "Mauro is a great player. He has been supportive of us on and off the field."
Even though he’s at the other of the pitch, David Ousted has seen the influence Rosales has had on the Whitecaps in his short time here.
"He's come in with a lot of experience," Ousted said. "Mauro knows this league and you can see just on his level that he’s a good player. He shows it every day in practice and every match that he means a lot to this team and brings some experience."
Rosales just sees that imparting of knowledge as part of his job and what should be expected of a veteran like himself. It must also have been very clear to him when he came to the club just how unpolished the Whitecaps strikers were.
He’s enjoying the time he’s getting to spend working with them, building up understandings of where each other will be and expected to be on the pitch, especially when it pays off like it did on Saturday.
"It's part of the work that we are doing with the guys", Rosales said. "We always talk about having minutes, having time with them. Everyday just knowing each other is much easier. As soon as I get more minutes with them, more days with them, I'll be much better.
"It's important for us to get the strikers playing up front goals and to get confidence. This is what we need for the last push."
Barring Manneh or Mattocks going on a tear, Erik Hurtado seems to have locked down the main striker’s position till the end of the season. Rosales has been working with him training, especially on link-up play between the pair, and even though there was no goal against Dallas, Hurtado’s workrate and hold-up play was excellent and better than what we’ve seen from him for much of the season.
"Seeing Erik today, running a lot, working very hard for the team to create space, just holding the ball, let us have a little bit of breath to manage the game and everything was outstanding today," Rosales felt. "Sometimes you have to do what you don't like best and sometimes you have to do what's the best for the team. He showed today a character and a professionalism and we are happy for that and also getting the three points against a very tough team."
And of that link-up play with Hurtado, Rosales added:
"We are getting better with each other. Sometimes we don't combine as much as we want, but sometimes the game just demands another thing, not just playing between the lines. He did very well today just holding the ball, even against three guys today.
The focus now from Rosales and the Whitecaps is on the massive game on Friday away to Seattle.
Portland’s come from behind win at San Jose on Saturday night kept the pressure on Vancouver and kept the ‘Caps playoff lead to a solitary point and it’s very likely that the Whitecaps will go into Friday night’s encounter behind the Timbers, as they play the Earthquakes again on Wednesday.
There’s also the smaller matter that a win for Vancouver sees them retain the Cascadia Cup, but a draw or a loss, sees the Sounders grab their fourth trophy, equalling the Whitecaps’ record.
For Rosales, it’s bound to be an emotional night as he heads back to Seattle.
Having spent three MLS seasons with the Sounders, he played against them for Chivas back in April. That was at the Stub Hub Center through and this will be his first game back in Seattle as a visiting player.
"It's going to be a very nice game for me, just coming back in front of the fans that gave me a lot of satisfaction when I was there, but now defending Vancouver," Rosales admitted to AFTN, but he's looking at the far bigger picture.
"We're in a position where we're needing everything from each other and we are going there to battle, to get the points. We are facing the leader of our Conference and everybody needs to be concentrating, facing the game like we did today and just trying to get the points. This is more important than just me going there."
Whenever I've written about Rosales for MLSsoccer.com, the love that the Sounders still have for the guy shines through in the comments, so does he expect to get a warm reception on Friday?
"I hope so," he told us with a smile. "I think I did very good over there and they always support me, even playing here, playing in Chivas, playing anywhere. They always support me and this is something I will appreciate forever and it's something really nice to have supporters from both teams just helping you out."
How much they'll support him if he grabs his first Whitecaps goal or contributes a couple of assists against them will remain to be seen! The story almost writes itself.