Vestas said it was appointing Chris Brown, who has served as chief operating officer for Detroit since early 2011. Brown is reported to have quit his role with Detroit three days ago.
Wyrsch is to leave Vestas in December. During her time in the role Vestas installed 4.7GW in North America and substantially increased manufacturing capability in the US.
With the upcoming expiry of the PTC, Vestas has been forced to make around 450 job cuts. Although this is substantially less than the 1,600 suggested by CEO Ditlev Engel.
In a statement, Vestas said Brown's first role would be implementing costs savings and "organisational adjustments".
As well as working for Detroit, Brown is a former CEO of Singapore Power International and vice president of Michigan utility DTE Energy.
Speaking about the departure, Vestas chief sales officer Juan Araluce said: ""Martha has led an ambitious effort at a time in which wind power growth is especially important. Under her leadership, we have safely and successfully managed a record installed base in two major countries committed to the benefits of clean, renewable and affordable wind power.
"As Martha informed me of her decision to continue her journey outside Vestas, we began searching for a strong profile to continue and enhance our efforts in North America. I am happy to have found a candidate that matches our expectations and I look forward to now working with Chris to continue our efforts."
Brown said: "I recognize there are many challenges in the U.S. wind industry," Brown said. "However, Vestas has tremendous potential and strength. This is evident in the management team, in the brand, and most important, in the many talented people who work at Vestas. I look forward to meeting the people behind the company’s success in the next few weeks and months.
"My approach will be to understand what we need to continue to do well and address those areas in which we can improve our operations. I’ve learned that building healthy relationships with customers, employees and the community is an important component to success."