SAN DIEGO -- Unlike in recent years -- when a flurry of mid-November trades became the norm for general manager A.J. Preller -- the Padres mostly handled their roster crunch in-season this year.

They promoted big-name pitching prospects Michel Baez and Adrian Morejon to the roster after the All-Star break, then they added Ronald Bolaños and David Bednar as September callups.

That left only one minor outfield shakeup ahead of the Wednesday deadline to protect players from the Rule 5 Draft. Left fielder Nick Martini was designated for assignment, clearing room for outfield prospect Jorge Oña to be added to the Padres' 40-man roster.

One of the biggest names out of the Padres' unprecedented 2016 international signing class, Oña hasn't quite lived up to his billing. The 22-year-old has batted .268/.342/.408 across three Minor League seasons, and he dealt with a torn labrum that sidelined him for much of the '19 season.

But in 25 games for Double-A Amarillo this year, Oña batted .358 with a .957 OPS. There are plenty of people within the organization who feel as though Oña can still develop into a corner outfield power threat -- hence the Padres' decision to protect him from the Rule 5 Draft.

The Draft will take place Dec. 12, the final day of the Winter Meetings in San Diego. To be eligible, a player must have gone through five Minor League seasons without being added to the 40-man roster -- or four if they were signed at age 19 or older. If a player is selected, he must remain in the Majors with his new club for an entire season or be offered back to his original team.

Among the noteworthy players who were left unprotected are two of the Padres' top 30 prospects, ranked by MLB Pipeline. Infielder Esteury Ruiz (No. 18) and outfielder Buddy Reed (No. 25) are now available to other clubs next month, as are outfielder Michael Gettys and righty relievers Trevor Megill and Dauris Valdez.

The Padres are obviously optimistic they'll be able to retain those prospects. They believe all five have Minors development time ahead of them, though with rosters set to expand to 26 players next season, it's possible another team takes a chance and adds one to its big league club.

As for Martini, who was claimed off waivers from Oakland last August, he's clearly no longer a part of the club's long-term plans. Martini was brought on board to address an imbalanced Padres outfield that crushed lefties but struggled against righties. He batted .244/.344/.317 in 26 games with San Diego last season.

There was speculation that Martini might factor into the Padres' 2020 squad as a platoon piece in the outfield. But it now seems likely Preller will address that deficiency via trade or free agency.

When a player's contract is designated for assignment -- often abbreviated "DFA" -- that player is immediately removed from his club's 40-man roster and 25-man roster, if he was on that. Within seven days of the transaction, the player must either be traded, released or placed on irrevocable outright waivers.