MOENCHENGLADBACH, Germany (AP) Borussia Moenchengladbach captain Martin Stranzl has undergone an operation on his fractured eye socket and will be ruled out for six to eight weeks.

The Bundesliga club says Stranzl underwent the operation at the Bethesda hospital Friday night after suffering the injury and concussion in the side's 3-0 home defeat to Hamburger SV.

The 35-year-old Austria defender was struck in the face by teammate Havard Nordtveit's elbow as both challenged Hamburg forward Pierre-Michel Lasogga for a high ball in the 65th minute.

Stranzl had just returned from a long-standing left knee problem and hadn't played since the 2-0 win at Bayern Munich on March 22.

`Gladbach is bottom of the Bundesliga with four defeats from four games. The side opens its Champions League campaign at Sevilla on Tuesday.