The shift back to the Eastern Hemisphere and, in part, to indoor hard courts begins this week in the ATP with tournaments at Metz and St. Petersburg.  The first of those marks the return of a top-10 threat from an extended injury.

Metz:

Top half:  Absent since Wimbledon with a knee injury, Jo-Wilfried Tsonga makes his tentative return at a home tournament on his favored hard courts.  The top seed and two-time defending champion can look forward to an early meeting against compatriot Jeremy Chardy.  Since reaching the Australian Open quarterfinals, Chardy has won only a handful of hard-court matches.  Of some note is the appearance of Federico Delbonis, a surprise finalist on Hamburg clay after he upset Roger Federer. Delbonis might catch Tsonga rusty in his first match since June, yet the Argentine has not proved himself on this surface.

While Frenchmen highlight the top quarter, Germans bookend the second quarter.  Fourth seed Philipp Kohlschreiber impressed at the US Open when he snatched a set from eventual champion Rafael Nadal.  Both Kohlschreiber and his projected quarterfinal opponent, Florian Mayer, translate their skills effectively across multiple surfaces.  Mayer never has defeated either his compatriot or Tsonga on a hard court, and Kohlschreiber also has struggled to contain the Frenchman’s explosive power.

Bottom half:  Despite disappointing results in Europe this year, Andreas Seppi has managed to stay inside the top 25.  That ranking has presented him with favorable seeds at small tournaments like Metz, where his slow-court grinding skills might leave him vulnerable to bolder shot-makers.  An intriguing test for Seppi might arrive immediately against Nicolas Mahut, who won the first two titles of his career this summer.  The Frenchman should relish the opportunity to shine before his home fans if he can survive the recently promising Leonardo Mayer.  More difficult to predict is how fifth seed Benoit Paire will respond to playing on home soil.  An enigmatic competitor at times, Paire has grown flustered under pressure and often achieved stronger results when flying under the radar.

Two monochromatic servers will square off on a surface that favors their styles.  In a demoralizing loss at the US Open, Sam Querrey could not break serve over the course of four sets.  Few onlookers would feel surprised if Querrey fails to break Ivo Karlovic over the course of three sets, for the tallest man in the ATP has recovered in fine form from meningitis.  A contrast in styles would await if either of these men advances to face Gilles Simon in a quarterfinal.  The second seed and wildcard missed the US Open, like Tsonga, with whooping cough.  One of the tournament’s more intriguing storylines might follow which of them can regroup more efficiently.

St. Petersburg:

Top half:  A surge through the summer clay season boosted Fabio Fognini’s ranking and recognition to unprecedented heights.  Now, Fognini holds the top seed at a tournament where he will seek his third title of the second half.  His main early threats might come from Ricardas Berankis or Lukas Rosol, the latter of whom has undergone a long losing streak after the death of his father.  Lithuanian phenom Berankis has regressed after showing early promise, but small tournaments like St. Petersburg might offer him the breathing room to regroup.

Having played two best-of-five matches on indoor clay in Davis Cup, Janko Tipsarevic might regret his plan to switch from that surface on Sunday to the indoor hard courts of St. Petersburg on Wednesday.  On the other hand, Tipsarevic needs wins of any nature to build on a second-week performance at the US Open.  That effort glimmered like the light at the end of a long tunnel after a 2013 littered with early-round losses.  Upset potential lurks near him in the form of Adrian Mannarino, a French shot-maker who can find his groove at unpredictable moments.  Far more dangerous, and far more unpredictable, is quarterfinal opponent Ernests Gulbis.  Enjoying the best season of his career, Gulbis defeated everyone outside the top 10 whom he faced on a hard court until Montreal, when he suddenly dropped three straight matches.  He routed Tipsarevic at Indian Wells this spring, but the Serb won their two previous meetings on indoor hard courts.

Bottom half:  Two summer standouts highlight the third quarter in St. Petersburg, one of them from the host nation.  Dmitry Tursunov reached three straight quarterfinals (and a semifinal) during the US Open Series, one of them as a qualifier at the Cincinnati Masters 1000 tournament.  Even more notable was the success of Fernando Verdasco, a surprise quarterfinalist at Wimbledon.  They did not shine at the US Open, however, Tursunov retiring with an injury and Verdasco falling in the first round.  A pair of giant-killers join Marcos Baghdatis among their challengers.  Sergiy Stakhovsky upset Federer at Wimbledon, and Horacio Zeballos stunned Rafael Nadal in South America.  Neither man has done much since then.

For periods of his matches against Novak Djokovic and Andy Murray this summer, Denis Istomin showcased shot-making talent that could bring him inside the top 20.  Before he fell to those top-four opponents, Istomin won a set from each of them as he lashed sparkling backhands down the line.  Unfortunately for him, the draw has placed him near second seed and US Open quarterfinalist Mikhail Youzhny.  This Russian veteran has reached three finals in St. Petersburg, winning one title.  A top-20 berth may have given Youzhny the confidence to double that total.