As it turns out, George Iloka was present for OTAs, but didn't practice due to a minor injury:
To clear it up, George Iloka is here. Just wasn't working on field. Is dinged up but nothing serious.— Paul Dehner Jr. (@pauldehnerjr) May 26, 2015
George Iloka was not on the field today. He is here in locker room. Injury nothing serious, anticipates practicing soon. #Bengals— Joe Danneman (@FOX19Joe) May 26, 2015
Paul Guenther said Iloka was just "dinged" should be out there soon.— Lindsay Patterson (@LndsPatterson) May 26, 2015
Hopefully, Iloka is back on the field soon as he enters a contract year.
Cincinnati Bengals safety George Iloka is noticeably absent from today's OTA session. According to reports, former third-round draft pick Shawn Williams has replaced him in team reps.
Iloka not on field— Geoff Hobson (@GeoffHobsonCin) May 26, 2015
Winston first team RT; Shaun Williams in for Iloka at safety— Geoff Hobson (@GeoffHobsonCin) May 26, 2015
No sign of George Iloka at first OTA. One of most interesting absences. Don't know that it means anything yet but worth noting.— Paul Dehner Jr. (@pauldehnerjr) May 26, 2015
Looks like George Iloka also isn't here for #Bengals. Has been around for workouts all offseason until now.— Coley Harvey (@ColeyHarvey) May 26, 2015
These sessions are voluntary, so we'll avoid fire-bombing the internet with speculation. However, it's worth noting that Iloka is entering his final year under contract.