Boyd has been loaned to first division CD Tondela this season, a move that Campelos wasn't completely in favour of.
"If I could, I would keep him with me for one more season," said Campelos. "But the club think it is better for him if he plays in the first league and for this reason they have loaned Tyler."
Boyd has already made his mark, with two goals in pre-season for Tondela.
"There's is no reason why he can't do well," said Campelos. "He is intelligent and always ready to learn. I'm sure he will keep growing as a player and he can reach high levels.
Now he will have the opportunity, in the first league, to show his football."
Boyd has certainly taken the road less travelled. When he arrived in Europe he was only a few months out of his teens, and he didn't speak any Portuguese. Adapting to the lifestyle wasn't that hard - the climate was inviting and the medieval streets of Guimaraes draw tourists from across Europe - but the football was a challenge. Boyd joined a club in the top six of the Primeira Liga, with dozens of talented youngsters keen to make their mark.
"He was a very good professional and a strong player physically," said Campelos.
"Technically he had some good qualities but he was a bit mechanical. And we saw tactically he needed to improve, and also the understanding of the game."
The Portuguese take a scientific approach to their football. It mixes the flair of Latin America, the organisation of Germany or Italy and the gamesmanship of the southern Slavic nations.
"Here we are very rigourous about your positions and your tactics," said Campelos. "You have to be. If you are not, instead of running two or three metres after that you must run 20 metres. And Tyler has learnt about things that are important here...like receptions in front, always looking for the ball between the lines of defence and midfielders. That's where we try to make the receptions. To play in front; if you watch the big players - Ronaldo, [Arjen] Robben, [Franck] Ribery - they always try to receive the ball and play in front."
Campelos also mentions that Boyd has become smarter - able to "win more fouls" - and touches on the psychological element to the game there.
"In Portugal, as a coach, we try to go inside the mind of the player," says Campelos. "It's very important. You don't have a penalty; you have a man that will score the penalty. You don't a free kick, you have a player who will make the free kick. Before the player, you must understand the person."
Apart from two matches for the first team, Boyd has spent most of his time in the Guimaraes B side in the Liga Pro, the Portuguese second tier, with 73 games over the past two seasons.
"It's a very strong league," said Campelos. "We have all the second teams of the big teams -Benfica, Porto, Sporting [Lisbon] - as well as the first teams of other clubs."
As an example, Barcelona's recent $47 million signing Nelson Semedo completed two seasons for Benfica B between 2014-16 while Paris St Germain winger Gonçalo Guedes was another recent graduate of the second division. Campelos feels that Boyd arrived last season, with eight goals and five assists in 34 games.
"The first season here was for him to know the league, the culture and the club, says Campelos. "Last season we have the confirmation of the capacity of him. Now he's ready to go. "