Ihenacho, who had a tough season with less of play time during the English Premier League season, was dropped due to “lack of fitness”.
In the last season, he came on for Leicester city as a substitute 21 times, started four times in the EFL cup and scored just one goal.
He featured just once for The Foxes in the 2018/19 FA Cup.
Ajayi, who had a splendid season with his championship side, also failed to scale the talents in the defence.
Rohr unveiled his squad after the team’s friendly 0-0 match against Zimbabwe on Saturday.
FC Midtjyland’s Paul Onuachu and Victor Osimhen of Royal Charleroi, Belgium, are the new call ups in the Super Eagles.
The team will depart for Egypt on Sunday aboard a chartered aircraft to set up a final training camp in the city of Ismailia.
The Eagles will take on Africa’s “number one” team, Senegal, in their final pre-AFCON friendly on June 16.
Nigeria will confront Burundi, Guinea and Madagascar in Group B of the 32nd continental tournament taking place in four Egyptian cities between June 21 and July 19.
Below is Rohr’s 23-man list for 2019 Afcon
Goalkeepers: Francis Uzoho (Anorthosis Famagusta, Cyprus); Ikechukwu Ezenwa (Katsina United); Daniel Akpeyi (Kaizer Chiefs, South Africa)
Defenders: Olaoluwa Aina (Torino FC, Italy); Abdullahi Shehu (Bursaspor FC, Turkey); Chidozie Awaziem (Caykur Rizespor, Turkey); William Ekong (Udinese FC, Italy); Leon Balogun (Brighton & Hove Albion, England); Kenneth Omeruo (CD Leganes, Spain); Jamilu Collins (SC Padeborn 07, Germany)
Midfielders: Mikel John Obi (Middlesbrough FC, England); Wilfred Ndidi (Leicester City, England); Oghenekaro Etebo (Stoke City FC, England); John Ogu (Hapoel Be’er Sheva, Israel)
Forwards: Ahmed Musa (Al Nassar FC, Saudi Arabia); Victor Osimhen (Royal Charleroi SC, Belgium); Moses Simon (Levante FC, Spain); Henry Onyekuru (Galatasaray SK, Turkey); Odion Ighalo (Shanghai Shenhua, China); Alexander Iwobi (Arsenal FC, England); Samuel Kalu (Girondins Bordeaux, France); Paul Onuachu (FC Midtjyland, Denmark); Samuel Chukwueze (Villarreal FC, Spain)