The Seattle Mariners and All-Star outfielder Julio Rodriguez are finalizing a long-term contract extension, sources told ESPN's Jeff Passan.

The deal is expected to guarantee Rodriguez more than $200 million, a source told MLB.com's Jesse Sanchez.

Rodriguez has put together a terrific rookie season and is a frontrunner to take home AL Rookie of the Year honors. The 21-year-old owns a .799 OPS with 20 home runs, 64 RBIs, and 23 stolen bases across 108 games this season.