The Argentine playmaker's experience could prove invaluable to Vancouver's aspirations.
It has been a week since the diminutive Argentine became a member of Vancouver Whitecaps FC, having arrived in a trade last Thursday from Western Conference rivals Chivas USA, with Nigel Reo-Coker heading the other way to The Goats.
Though the arrival of Rosales adds another playmaker to Vancouver's ranks, the 33-year-old's impact as an MLS player would suggest that head coach Carl Robinson might have pulled off a bit of a coup in landing the South American veteran.MORE: Alex Morgan upset at 159-degree temps | Transfer photos
Though he appeared as a second-half substitute in last weekend's defeat at LA Galaxy, Robinson was instantly impressed with Rosales' qualities in his 'Caps debut.
"In hindsight, I probably should have started him," said the former Wales international. "He brought energy to the field, he brought a calmness. He wasn't afraid to put his foot in and his head in where it hurts and he linked up with Pedro (Morales) very well, which I thought was very interesting."
At Wednesday's training session at the University of British Columbia, Rosales did not look like the new kid on the block, but more like the new mentor for some Vancouver's younger players.
Towards the end of the training session, the former River Plate and Ajax man was offering guidance to Kekuta Manneh on making attacking runs down the flanks. That was followed by a conversation with members of the Whitecaps' Hispanic contingent in the middle of the club's training pitch.
"Just trying to be helpful is one of the things that always works in this time of my career," Rosales told reporters. "I've been on the other side, just being young and spending the right energy on the field.
"We have a quality team, but everybody needs to have that willingness to get better and willingness to be successful in the team. They are young and they have time ahead of them to accomplish any goals that they have. We'll be fine if I'm close with them and I just share my experience in what I've done in my last teams."
Having registered the second most assists (42) in MLS since 2011, Rosales is expected to offer quality crosses and set-pieces to Whitecaps' strikers, especially from the right-hand side.
"Mauro offers excellent delivery and distribution," said Robinson. "The formation that we play, he fits in very well to that. He brings a little bit of guile that we've probably been lacking over the last couple of games. Coming in on that right side, Mauro likes to play out to in. It's just a different personnel and option change with experience."
The likes of Manneh, Erik Hurtado, Darren Mattocks, and Omar Salgado should benefit from what Rosales can provide to set up scoring chances. However, it remains incumbent for Vancouver's young attack force to convert those opportunities.
Of late, goals have been barren from the Blue and White, with the club's form suffering as a result. Where Rosales may prove invaluable is in his ability to create an understanding with his new teammates that unlocks the well publicized scoring potential of his new club.
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This weekend, Rosales has the opportunity to become an instant fan favourite in Vancouver, should he earn a start in Saturday's crucial encounter with Pacific Northwest rivals Portland Timbers at a sold-out BC Place.
The playmaker is no stranger to Cascadia Cup matches, having played his fair share of Pacific Northwest derbies during his three seasons with Seattle Sounders FC. Having experienced big derby games in his native Argentina and the Netherlands, Rosales knows how important a game like Saturday's is at any stage in the season, let alone the fact that it is a pivotal playoff-deciding encounter.
"Derbies are rivalries that everybody wants to play in and make history," Rosales said. "It's a game where there are not just 22 players playing on the field, there is rivalry in the stands with supporters, who are also involved. I always like to play these games because the atmosphere is fantastic, and in this region, it has been amazing the last couple of years."
While Rosales' arrival boosts the Whitecaps' attacking creativity, general consensus remains that Vancouver still needs an experienced goalscorer. With a little more than two weeks left before the MLS roster freeze, it remains to be seen if Robinson has one more transaction to complete for the season run-in.
As Whitecaps fans keep a close eye on those potential developments, there is a sense in Vancouver that landing a player like Rosales answers many of the lingering questions regarding the 'Caps attack this season.
If that proves to be the case, then Robinson may have pulled off one of the best MLS trade deals in recent memory.