Burdi (elbow) began a rehab assignment with High-A Bradenton on Monday.
Burdi will make his first competitive pitches since undergoing Tommy John surgery last May. The length of his absence means he'll need a long rehab assignment before being considered for major-league action, though the Pirates will have to call him up once his rehab stint ends as he was selected in the Rule 5 draft over the offseason. So far in his professional career, he's topped out at the Double-A level, recording a 3.17 ERA there in 63.2 innings with the Twins' Chattanooga affiliate.