The 28-year-old Kiprotich produced his lifetime best of 2:06:33 in Japan with his runner-up finish in Tokyo that year. In April's Hamburg Marathon, his most recent race over the distance, he finished second in 2:07:31.
Karoki, 27, will be making his second career appearance over the distance, following up on his 2:07:41 debut performance at the London Marathon in April where he finished third. Boding well, in his most recent appearance Karoki improved his personal best to 26:52.12 over 10,000m at the IAAF World Championships in London, finishing fourth. In February, Karoki won the RAK Half Marathon in Ras Al Khaimah in 59:10, also a personal best.
Meanwhile, the fastest man in the field is Tsegaye, who clocked 2:04:48 to win the Rotterdam Marathon in 2012. The 32-year-old Ethiopian won in Fukuoka last year in 2:08:48, to collect his ninth career marathon win. He'll be aiming to regroup from a sub-par 2017 season in which he finished a distant 12th at the Boston Marathon, clocking 2:16:47. He did not finish the World Championship race in London, his most recent outing.
Others to watch include Kenyan Lani Rutto, whose 2:06:34 marks him as one of the field's fastest. But the 28-year-old hasn't come close to that 2015 effort from Frankfurt since. He didn't finish May's Prague Marathon, his only attempt at the distance this year.
The field also includes Amanuel Mesel of Eritrea, who has a personal best of 2:08:17 from 2013, and Sondre Moen, the Norwegian record holder at 2:10:07. Daichi Kamino, a 1:01:04 half marathoner who excelled at the Hakone Ekiden earlier this year, will be making his eagerly anticipated debut.
Bob Ramsak and Ken Nakamura for the IAAF