The Hokkaido Nippon Ham Fighters' bid for a league championship took a hit on Tuesday, when closer Chris Martin was deactivated due to an ankle sprain.
The 203-cm right-hander, who became the team's closer on June 19 and was named to the Pacific League All-Star team, suffered a left ankle sprain in Sunday's 7-7, rain-hit tie against Orix in Kobe. The injury is expected to sideline him for about four weeks.
"I think it's unlikely he'll be available before the end of the regular season," manager Hideki Kuriyama said.
The 30-year-old Martin has pitched in 52 games, with a 1.07 ERA, 19 holds and 21 saves this season.
The Fighters started Tuesday in second place, one game back of the PL-leading Fukuoka SoftBank Hawks. The Fighters' game on Tuesday was rained out.