Frankel's brother has been named in the 475 entries for the 2016 Derby at Epsom.
The owner of the unnamed colt, Khalid Abdullah, also has a son of Midday - winner of six Group One races - among his entries.
There are two more entry stages before the race for three-year-olds on 4 June.
Frankel - once the highest rated racehorse in the world - was unbeaten in his 14-race career, winning the 2000 Guineas and Sussex Stakes.
Another younger brother, Noble Mission, won the Champion Stakes at Ascot this year for trainer Lady Cecil, the widow of Frankel's trainer Sir Henry Cecil.
Frankel was retired to stud in 2012 after winning the Champion Stakes.