The 26-year-old Dutch rider took a step down from the WorldTour last season and joined a continental team for 2014, but after a good start to the season he will now join the team for the rest of the year.
Bulgac’s first race with the team will be the Rund um den Finanzplatz Eschborn-Frankfurt (1.HC) on 1st May in Germany.
Bulgac said: “I am very thankful for the opportunity that Team Giant-Shimano have given me to allow me to return to the WorldTour and to continue progressing at the top level of the sport.
“Last winter I unfortunately I had to take some steps back in my career, and made the step down to join a continental team at the start of the season, with a much reduced race program.
“However, I got in touch with the coaches of Team Giant-Shimano and was invited to a team training camp at their training base in Spain.
“The training camp was a test to see whether cooperation from both sides was possible, as well as to get to know one another and to see if there was a fit.
“We spoke about my development as a rider and in which direction I wanted to go and how the team could help me to progress towards this goal. For me personally it is a totally different approach than what I am used to.
“I learned more about teamwork during that week, getting lessons from both the riders in the team as well as the different specialists with whom I connected to get the maximum out of me in all areas both as a cyclist and as a person.
“I am happy that I can continue on the path of become a consistent professional. I am more motivated than ever, I am working hard and I feel that I am already getting stronger.”
Team Giant-Shimano coach, Rudi Kemna (NED) added: “We do not just hire any rider, but we hire riders who we think have the skills and the mindset to make steps in their development – and Brian is such a rider.
“We didn’t want to force such a decision in a short period of time (after he was out of contract) but we preferred to get to know him and work with him at a training camp to see if both parties could work well together.
“We see him developing into a rider in the team for the difficult one-day races and also for stage races and we look forward to developing alongside one another.”