Champion Al-Attiyah wins WRC 2 in Portugal
Qatari moves second in points standings
Ketomaa, 36, injured an eye when he crashed on the final day of Vodafone Rally de Portugal in June and he was troubled by vision problems during 72nd LOTOS Rally Poland earlier this month.
Acting on the advice of an eye specialist, Ketomaa will sit out the event to give his eye time to heal naturally.
Ketomaa was one of the favourites to win WRC 2 in Finland (30 July - 2 August), having claimed a first and second place in the last two editions.
“I’m obviously disappointed to miss my home event, especially knowing we have the pace to win and strengthen our championship lead," he said.
"But I need to think about the rest of the season and follow the specialist advice to allow the damage to heal. I’m confident Jarkko will do a good job for the team.”
Competing in Finland's world championship counter for the ninth time, Nikara, 29, will be co-driven in the Autotek-run Ford Fiesta R5 by Kaj Lindstrom.
In 2013 Nikara impressed by running as high as sixth in a MINI John Cooper Works WRC before a damper problem forced him out on the final day.