Zenit's Belgian defender Nicolas Lombaerts is in "satisfactory condition" in a St. Petersburg clinic after suffering a concussion from a head clash during Sunday's 1-1 Russian Premier League draw with Rubin Kazan, the club said.
Lombaerts will remain under observation at least until Monday after colliding midair with Nelson Valdes, the Rubin goal scorer, during the match, the club said.
Both were substituted and taken to hospital.
"At the moment [Lombaerts] is in satisfactory condition, his expected recovery time will be made clear later," Zenit said on its website.
Lombaerts joined Zenit in 2007 and has eight goals in 89 appearances.
Valdes' condition was not clear, although the Zenit statement said "according to preliminary information he received the same injury."
Szabolcs Huszti scored Zenit's opener before Valdes equalized, a result that extends Zenit’s lead over second-placed CSKA Moscow to seven points.
