(Reuters) – New York Yankees first baseman Greg Bird will undergo surgery to remove excess bone growth from his right ankle, putting his season in jeopardy, the American League club said on Monday.

Bird, a power-hitting prospect who had been projected to be the starting first baseman this season, is batting just .100 while playing in 19 games this season after missing all of the 2016 campaign following shoulder surgery.

“It’s really tough to get on track when you missed two really whole years,” manager Joe Girardi said before Monday’s game against the Twins in Minnesota.

Bird is expected to resume baseball activities in September with the regular season ending at the end of that month.

Excess bone growth in the back of his ankle was believed to be the cause of the inflammation that has limited him to just 60 at-bats this year, the club said. The 24-year-old is to have surgery on Tuesday.

Bird appeared to be on track for a big season when he batted .451 (23-for-51) with eight homers in 23 spring training games, but he became hobbled after fouling a ball off his right ankle in one of the last warm-up games before the start of the regular season.

He tried to play through the pain before heading to the disabled list with what the team described as a bone bruise.

Garrett Cooper and Choi Ji-man of South Korea have both been playing at first base for the Yankees, who have started eight different players there this season.