Valencia attacker Juan Mata was removed from training today following an accidental collision with team-mate David Navarro and is a major doubt for the weekend fixture against Racing.
The Spanish international winger was competing in a bounce match and suffered a bruised shin which forced him to miss the remainder of the session.
Navarro, however, come off worst in the incident, sustaining what medics initially diagnosed to be a sprained ankle, and he was transferred to hospital to undergo further tests to ascertain the full extent of the problem.
Los Che coach Unai Emery involved the entire squad in training drills specifically designed with his tactics for the trip to Cantabria on Saturday in mind.
However, the injuries sustained by both players are likely to forced the former Almeria boss into a rethink, as he waits for confirmation of whether both players can participate.
Valencia are currently enjoying a five-match winning streak in the Primera Division and lie in fourth position in the table.