The Padres placed Lamet on the 10-day injured list Thursday with a right UCL strain.
Lamet's injury dates back to last September, but his placement on the IL is the result of him not being fully ramped up rather than any major concern about his health on the Padres' part. After working 1.1 innings in his final spring-training outing Monday, Lamet will likely need at least a couple more weeks to get fully conditioned for starting duty. Adrian Morejon is expected to serve as San Diego's fifth starter until Lamet is ready to make his 2021 debut.