With teams able to expand their rosters to 40 men on September 1, who should the San Diego Padres call up for the final month of the season?

It’s no secret that the San Diego Padres have one of the best farm systems in major league baseball. They rank number one on several lists and their minor league affiliates ooze talent at all positions on the field.

As we approach September, the Friars might be thinking about a potential player or two to call up with the roster expansion that accompanies the change in seasons. Last year that person was Francisco Mejía, the former Cleveland Indians number one prospect who San Diego acquired after trading away Brad Hand and Adam Cimber.

A reminder on how the roster expansion works: currently, the Padres can only field a player if he’s on the 25-man active roster. If they want to bring someone up from the minors who’s already on the 40-man, they can “call him up” by placing him on the active roster.

Of course, a player would need to be removed from the 25-man to make room for the new guy, either by “optioning” a player, replacing someone who joins the 10-day IL, or placing him on outright waivers.

These transactions aren’t required in September. With the active roster expanded in the final month of the season, the Padres could field anyone on the 40-man roster without needing to bump another player off the 25-man.

The team won’t actually bring 15 new players to Petco, since most of the guys not on the active roster are playing in the minors. Each team generally adds at least a player or two for a variety of reasons though.

Anyway, things get a little more complicated if the Padres call up a prospect who’s not on the 40-man roster. In that case, they’d need to clear a spot in order to make room for the newcomer.

They could do this by designating a player for assignment, making a waiver trade, placing him on the 60-day IL, or releasing him outright.

Now that there’s an available spot on the 40-man, the team could select the newcomer’s contract and place him on the roster.

With all that said, the Padres would clearly need a good reason or incentive to put a new player on the 40-man roster. Some reasons might include wanting to give a top prospect some experience in the majors after crushing the minors, or if they’re protecting him from the Rule 5 draft.

Furthermore, this is the last season in which the MLB will allow the 40-man roster expansion — starting in 2020, the season’s active roster will increase from 25 to 26 players and September will see a roster expansion of only two players, from 26 to 28. All MLB teams will be required to carry 28 players from August 31 through the end of the season.

Let’s take a look at three potential players should the San Diego Padres call up a prospect or two come September.