Hockey India`s decision to drop three players, including veteran midfielder Manpreet Singh, from the list of probables for the upcoming FIH Pro League season stemmed from "serious disciplinary" issues during the team`s tour of South Africa in December.

Sources said that in the wake of alleged indiscipline during the three-Test tour, Manpreet Singh, Dilpreet Singh and goalkeeper Krishan Bahadur Pathak were left out of the 33-member probables` list for the national preparatory camp, scheduled from February 1 to 7, ahead of the upcoming FIH Pro League season.