Nairobi, Return of Olympic 1,500m champion Faith Kipyegon to action after two years' maternity leave will likely shake up the pecking order in the four-lap race at the World Championships starting in Doha on Friday.
World No. 1 Sifan Hassan has demonstrated her middle-distance supremacy in 2019 by recording the world's fastest time of 3:55.30 in Monaco on her way to the world mile record as well as claiming an emphatic 1,500m victory at the IAAF Diamond League final in Zurich.
Whereas Kipyegon was fifth in Moscow in 2013, second in Beijing 2015 and won in London in 2017.
"My goal is to go to Doha, to defend my title," Kipyegon told reporters in Nairobi.
"After being out for such a long time, you don't exactly know where you are at, so it was great to test myself at the Prefontaine meeting in the U.S. I, however, skipped the Birmingham race to avoid getting worn out."
Kipyegon could step up to retain her title after taking a year out of the sport in 2018 to give birth to daughter Alyn.
The Kenyan who is also the Olympic champion made a triumphant return to the track with victory at the IAAF Diamond League meeting in Stanford in June but picked up an adductor injury.
"I did not run in Birmingham as a precaution against the injury. I wanted to rest and let it heal fully. I think I am in good shape and will run a good race in Doha," she added.
Kipyegon's only other competitive race this year came at the Kenyan Trials earlier this month in Nairobi, where the ever-smiling Kenyan claimed an important victory.
But it is not yet known whether the U.S.-based Dutchwoman Sifan Hassan, who is also entered for the 5,000m and 10,000m, will compete in the 1,500m.
She will only make a call on which of the shorter events to contest after her 10,000m final, but the current indications are that she will opt for the 5,000m over the 1,500m.
If Hassan does not line up for the 1,500m, the event becomes more open, and even more so after Genzebe Dibaba, the 2015 world champion, was a late withdrawal due to plantar fasciitis.
Britain's European champion Laura Muir was in cracking form over the first half of the season, highlighted by a 3:56.73 performance for second place in Rome. However, a calf injury put the brakes on the preparation and it is not yet known how that has compromised her fitness.
Others are Germany's Konstanze Klosterhalfen, Ethiopia's Gudaf Tsegay, who set a personal best of 3:57.40 in Rabat and as a consistent performer on the IAAF Diamond League circuit and Kipyegon's compatriot Winny Chebet and Winnie Nanyondo of Uganda.