The Watch List highlights the must-know storylines for the upcoming week in tennis. This week, Venus Williams leads the pack in the WTA International-level event in Istanbul, while Sara Errani, Sam Stosur and recent winners Anna Karolina Schmiedlova (Bucharest Open) and Johanna Larsson (Swedish Open) head to the red clay in Bad Gastein, Austria. For the men, David Goffin tops the field in the ATP 250 tournament in Bastad, Sweden, and Gael Monfils is the No. 1 seed in Umag, Croatia. After his loss in the Newport final to Rajeev Ram on Sunday, Ivo Karlovic makes a quick turnaround as the top seed in Bogota, Colombia.
Nurnberger Gasteinladies 2015 (Bad Gastein, Austria)
No. 1 seed Sara Errani, who is coming off a loss in the Bucharest Open final to Anna Karolina Schmiedlova on Sunday, is the only top 20 player in the field on the clay courts in Bad Gastein. After an early loss in Bucharest last week, Sam Stosur is looking to rebound as the second seed. Rounding out the field are Schmiedlova, Karin Knapp, Carina Witthoeft, Lucie Hradecka, Julia Goerges and Katerina Siniakova.
TEB BNP Paribas Istanbul Cup (Istanbul, Turkey)
Venus Williams leads the field on the hard courts in Istanbul, where Caroline Wozniacki was the champion in 2014. Venus could play Bastad runner-up Mona Barthel in the second round and is joined by No. 2 seed Elina Svitolina and Jelena Jankovic, who took down 2014 Wimbledon champion and then-World No. 2 Petra Kvitova at the All England Club this year. Camila Giorgi, Daria Gavrilova, Anastasia Pavlyuchenkova and Tsvetana Pironkova are also in the field, as well as Alize Cornet and Dominika Cibulkova.
Claro Open Colombia (Bogota, Colombia)
After six weeks of grass court play, the ATP tour returns to clay and hard courts. Tennis Hall of Fame Championships runner-up Ivo Karlovic is the No. 1 seed in Bogota, where he lost in the final in a third set tiebreaker to Bernard Tomic last year. The big-serving Croatian has hit 202 aces in Bogota (104 in 2013, 98 last year). After he was arrested in Miami Beach last week over hotel music, 22-year-old Tomic returns as the second seed and defending champion. He is joined by third-seed Adrian Mannarino and fourth-seed Victor Estrella Burgos in the top four. Marcos Baghdatis, Sam Groth, Malek Jaziri and James Ward are also in the field.
Skitsar Swedish Open (Bastad, Sweden)
David Goffin is the top seed in an ATP tournament for the first time in his career in Bastad, after David Ferrer and Guillermo Garcia-Lopez both pulled out of the tournament. Goffin is joined by former two-time winner Tommy Robredo, defending champion Pablo Cuevas and 2009 runner-up Juan Monaco. The draw also sees two of the ATP's rising teenage stars in action in 18-year-old German Alexander Zverev and 19-year-old Elias Ymer from Sweden.
Konzum Croatia Open Umag (Umag, Croatia)
In his second appearance in Umag, World No. 17 Gael Monfils is the top seed, followed by Roberto Bautista Agut, Andrea Seppi and Dominic Thiem, who just moved to a career-high No. 26 in the ATP Rankings this week. No. 5 and 2013 runner-up Fabio Fognini, Philipp Kohlschreiber, Martin Klizan, Borna Coric and 17-year-old Russian Andrey Rublev are also in the draw.