Janish, 25, played in Friday's game against the New York Yankees and batted .200 (4-for-20) in 15 spring games.
Dickerson, 25, had appeared in 16 games and was hitting .233 (7-for-30) with a homer and four RBIs.
Lehr had not allowed a run in three games covering 3 1/3 innings. A 30-year-old non-roster invitee, Lehr had allowed two hits, no walks and had struck out three.
The moves left the Reds with 54 players in camp, counting pitcher Bobby Livingston, who is on the 60-day disabled list.
Jim Molony is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.