Maria Sharapova looks the same, shrieks the same, and still has the trademark tenacity that is so sorely lacking among many of the women on the WTA Tour. Unfortunately, Sharapova no longer has the deadly serve that helped her win three major titles.

Will she ever get it back? It’s still early in her comeback from October 2008 arthroscopic surgery on her right shoulder, but there are concerns that her new abbreviated service motion—a style made popular by Andy Roddick—might cause her more damage in the future, rather than less. As one observer close to Sharapova (who declined to be identified) put it, “If anything, the adjustments they’ve made are heading in the wrong direction.”

Robert Lansdorp, the esteemed coach who helped to develop Sharapova’s killer strokes, was more blunt after watching Sharapova double fault 16 times as she lost to Flavia Pennetta in the Los Angeles semifinals two weeks ago. (She also double-faulted 17 times in Toronto Wednesday, but won in straight sets.)

“It’s atrocious, plain atrocious,” Lansdorp said. “Instead of keeping it simple, they make it so complicated for her. She bends down way too much. Her elbow drops. She falls down with her face to the left. It’s so atrocious. I used to tell her, throw a football. If she threw a football with that motion, it would hit her right smack in the face. She’s going to get injured more because she is using way too much body. She doesn’t really rotate [her shoulders] that much, she just bends a lot.”

A member of Sharapova’s camp, who also asked not to be identified, urged patience. Indeed, considering the extent of her injury, the months she spent away from the game, and the relatively little time she has had to work on the new motion, Sharapova has performed quite well this summer, reaching the quarterfinals of the French Open and collecting three victories over Top 10 players. In Los Angeles, she played four night matches in five days and in the fourth led Pennetta 3-1 in the third set before tiring. Sharapova aims to be at full strength for next season’s Australian Open and will play on two tournaments after the U.S. Open, in Tokyo and Beijing.

Despite a number of grueling matches this summer, Sharapova’s shoulder has held up well. Unfortunately, there’s no going back to the slower, longer motion that she relied on earlier in her career. Biomechanics experts say there’s little difference between a long and short service motion, in terms of stress on the arm and shoulder, once the forward swing begins. Sharpova’s is a peculiar case, though: Her shoulder is so loose and flexible that her rotator cuff used to move during her windup. The goal of the new motion is to limit her shoulder movement before she goes after the ball.

Nick Bollettieri, whose academy took on Sharapova when she was 8 years old, has not worked with her on the motion, but he too has concerns with what he’s seen so far in her return to competitive tennis.

“Not knowing the whole story, I’m very reluctant to criticize,” Bollettieri said. “But what I would do is what Andre Agassi and Boris Becker told me many times—listen to your student. Start with what’s comfortable, and then maybe do a little tinkering.”

Even without a first-rate serve, Sharapova has the talent to return to the Top 10. But Bollettieri, for one, isn’t convinced that she can be as good as she was in early 2008, when she won the Australian Open without losing a set, unless she finds comfort with her new serve soon.

“If you begin to doubt one of your big weapons, that’s tough, especially in today’s game,” he said. “We all know how competitive she is, but competitiveness can only take you to a certain point.”

Tom Perrotta is a senior editor at TENNIS. Follow him on Twitter.