However, Lokomotiv said stringent medical tests conducted in Italy did not reveal any issues that would prevent Howedes from joining the club.
Howedes spent 16 years at Schalke, progressing through the club to become first-team captain. He played in 240 Bundesliga games and was a member of the side who won the DFB-Pokal in 2011.
"Last summer, Benedikt looked for a new challenge at Juventus," said Schalke's sporting director Christian Heidel.
"We wish him all the best in the new sporting chapter of his career at Lokomotiv Moscow, who did a remarkable job last season."