The Golden State Warriors are expected to buckle down to serious work as they try to defend their NBA crown, but it seems that they will have to start without head coach Steve Kerr at least for now.

Kerr underwent surgery to fix a herniated disc, undergoing two off-season back surgeries that would need him to take some time off.

There is no timetable for his return, but in his place will be Luke Walton.

Walton was recently promoted to lead assistant coach of the Warriors after the departure of Alvin Gentry who is now the head coach of the New Orleans Pelicans.

"To be honest, the last couple of months have stunk for me," Kerr told reporters, adding "I'm not kidding. I've had a rough go physically this summer."

Apparently, the time-off is a must. His return could likely depend on how well he is able to respond to rehab, although the Warriors don't expect the first-time champion coach to be out for long.

Such is seen as a minor setback as the Warriors dig into training camp. Kerr thus remains questionable as well as far as being ready by the time the 2015–16 NBA season opens near the end of the month.

"At this point, the most important thing is to make sure Steve is healthy, completely recovered and ready for not only the rigors of a long NBA season, but day-to-day life in general," said Warriors General Manager Bob Myers, as posted on NBA.com.

The Warriors are expected to be in for a tough season, especially since they find themselves in a pretty competitive Western Conference.

With Walton, however, the Warriors don't seem to mind and are in fact confident he can fill in for the time that Kerr is out.

"Luke is fortunate enough to have played and coached under some great coaches," said Myers, according to CSNBayArea.com. "He has an innate ability to think the game, to learn the game and also to communicate the game," he added.