Cinicinnati shortstop Jose Pereza will move to second base in Gennett's absence while Jose Iglesias will start at shortstop.
Reds second baseman Scooter Gennett is expected to miss eight-to-12 weeks with a right groin strain, according to MLB.com's Mark Sheldon. Gennett suffered the injury while fielding a ground ball off the bat of Yasmani Grandal in a spring training game against the Brewers on Friday.
The Reds' top prospect Nick Senzel will begin the season in AAA. He has played second and third base in the minor leagues, but has been in centerfield for a large share of spring training. Senzel coud join Cincinnati in late April.
Gennett joined the Reds in 2017 after four years in Milwaukee, hitting 27 homers and driving in 97 runs in his first year in Cincinnati. He was named an All-Star for the first time in 2018 with a career-best .310 average.