Cincinnati Reds pitcher Nick Lodolo is out indefinitely after an MRI revealed a stress reaction in his left tibia.

Reds manager David Bell said Lodolo is in a walking boot and will undergo another MRI in two weeks before the team determines a timeline for his return.

"He's still at the beginning stages of being in a boot and letting it heal," Bell told reporters, according to the Cincinnati Enquirer. "He's pretty limited right now -- limited him on purpose, so he can heal before he takes any next steps."

Lodolo was placed on the 15-day injured list Sunday with what the team initially diagnosed as calf tendinosis. The left-hander returned to Cincinnati last weekend for follow-up tests and Bell said the upcoming MRI in two weeks would be a "big milestone."

Lodolo, 25, got off to an outstanding start this season, recording 27 strikeouts in 17 innings over his first three starts. But he struggled in the ensuing four starts before being placed on the IL and currently has a 6.29 ERA while leading the National League in home runs allowed (10) and hit-by-pitches (seven).

The seventh overall pick in the 2019 draft, Lodolo went 4-7 with a 3.66 ERA in 19 starts as a rookie last season.

Information from Reuters was used in this report.