Nadal's safe serve could spell trouble this summer

Rafael Nadal won a title this past week, but what does it really mean as the summer hard-court swing takes off? Our staff weighs in on Rafa and other recent news.

More shake-ups for del Potro

Leo Ayala, ESPN Deportes: Despite seeing no action, the past few months were anything but quiet for Juan Martin del Potro. Not only did he undergo left wrist surgery again, but he also joined the Argentina Davis Cup team twice during its World Group rubbers (Delpo even hit some balls with them in July) and decided to change his coaching staff.

After seven years, Del Potro will no longer work with coach Franco Davin and physical trainer Martiniano Orazi, who was important in providing support and contention every time his injuries kept him off the courts. But the Argentine player, who has just started physiotherapy, has already stated he is no hurry to make any replacements.

Del Potro tried to make it clear that this decision is not the beginning of a new crisis -- and tried to dissipate doubts about his return to professional tennis.

"This is a new beginning," del Potro told the press. "I am more determined than ever to walk the path toward my return. No more doubts, no more question marks."

Del Potro may sound sincere, but without a coaching team around him and with no return date, doubts and question marks are the only certainties.

Nadal playing it safe

Carl Bialik, FiveThirtyEight.com: With a brief stint back to the comfort of clay, Rafael Nadal won the German Open last week in Hamburg. It was his first title above the 250 level in more than a year, albeit in a weak 500-level field in which he was the only top-20 player. In doing so, Nadal moved up one spot to No. 9 in the rankings. He's in a good position to move into the top eight before the U.S. Open, thereby avoiding meeting any other top eight players before the quarterfinals.

But Nadal's title came with a baffling asterisk: He hit his first serve no better than his second serve. If anything, his second serve was more effective. His first serve went in 76.9 percent of the time, and when it did, he won the point 62.6 percent of the time. His second serve went in 80.6 percent of the time (the rest of the time he double-faulted), and when it did, he won 62.9 percent of the time.

Nadal has always hit his first serve more safely than the usual ATP player, content to use it to set up his forehand. But his best hard-court campaigns have been boosted by a big first serve. Against tougher competition on the summer's faster courts, he'll need bigger serving than he delivered in Hamburg.

Thiem making his move

Peter Bodo, ESPN.com: Twenty-one-year-old Facebook junkie Dominic Thiem of Austria won his second title in as many weeks at the Swiss Open on Sunday, hammering 14th-ranked David Goffin 7-5, 6-2 in under 90 minutes.

The triumph added a third title to Thiem's haul thus far in 2015. He won the first ATP title of his budding career at Nice, France, in May. Then he won at Umag, Croatia, the week before last.

This week, Thiem returns to his native Austria to play on the clay at Kitzbuehel. Could we be looking at another of those sensational runs in which a promising young player makes his long-awaited move to the big time?

The kind of move Grigor Dimitrov has not made?

The kind Bernard Tomic never made?

The kind of move hard-luck case Juan Martin del Potro made in 2008 at the age of 20 when he won his first four titles in consecutive weeks (two on clay in Europe, two on North American hard courts) to vault into the limelight?

Thiem, now up to No. 21 in the rankings, leads the pack of players who are 21 or younger. His nearest challenger is promising Croatian youth Borna Coric, ranked No. 33, followed closely by Aussie Nick Kyrgios at No. 38. Nobody else in that age group is inside the top 50.