Zoidl joins the team from Team Gourmetfein Simplon, and in July, became the first Austrian to win his home tour in five years among his 14 victories so far in 2013.
"My hope is that I can keep developing as a rider with the Trek team," said Zoidl. "I'm very excited about this. It's a dream come true. I had other possibilities, but this project looks really solid and promising to me. I'll be able to learn and accomplish a lot here."
Other victories include the Circuit des Ardennes, Tour de Bretagne, the Austrian Hill Climb Championship and the Austrian Road Championship where he defeated Stefan Denifl (IAM Cycling). Zoidl is also a two-time winner of the national time trial championship.
"Riccardo is a very complete rider, who performs well in many disciplines," general manager Luca Guercelina said. "We had him on our radar before, but after the Tour of Austria, we looked into him. We want to give them opportunities to grow here, especially in the smaller stage races."
Arredondo meanwhile, is currently in his second season with Team Nippo-De Rosa. The 25-year-old has had a big year racing the UCI AsiaTour, winning the overall at both the Tour de Langkawai and the Tour de Kumano. He was also second overall at the Tour of Japan, winning the young rider classification.
"I'm incredibly thankful for this opportunity. Every day I wake up and I couldn't be happier," Arredondo said. "It's very hard for young people to make a future in my country. This chance is huge for me. I'll try to make everything out of this and will show every day that Trek was right to pick me."
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Guercelina said that Arredondo was tested by the team with promising results.
"His attitude is also very good," he explained. "He'll be a strong support for our leaders in the climbs."
The Trek WorldTour team has previously announced that Stijn Devolder, veteran Yaroslav Popovych, Kiwi pair Jesse Sergent and Hayden Roulston, Gregory Rast, Andy and Fränk Schleck, Fabian Cancellara, Jens Voigt, Fumiyuki Beppu, Haimar Zubeldia and fellow Spaniard Markel Irizar have also signed for 2014.
