As September roster expanders loom, contenders weigh top prospects like Josue De Paula and Franklin Arias

September is only days away, and for MLB contenders the final month often turns into a management exercise as much as a baseball one. On Sept. 1, teams are allowed to add two players to the roster for the stretch to the postseason, with the constraint that no more than one of those additional players can be a pitcher. CBS Sports’ look at who could be called up for that purpose frames the decision as less about “who is best on paper” and more about who can help immediately as workloads climb and the margin for error shrinks.

That roster expansion structure matters because it narrows options. Teams do not get the broad Sept. call-up flexibility that existed under earlier rules. Instead, the new limit effectively forces front offices to prioritize specific gaps they expect to encounter over the last few weeks, such as late-inning relief needs, bench depth in key matchups, or an everyday-ready bat that can absorb at-bats without disrupting the clubhouse rhythm.

CBS Sports highlighted Josue De Paula and Franklin Arias among prospects it views as potential contributors during that roster expansion window. The emphasis on “waiting in the wings” underscores the common reality in September: organizations can move only a small number of players, so the list is typically built around a mix of readiness, role fit, and how the team’s existing roster can cover the rest.

The practical question for every contender is how those two slots should be used. One approach is to secure bullpen leverage for a stretch where multiple innings are often required in quick turnarounds, especially when a team’s best relievers are already stretched from months of late-game innings. The rule that only one additional pitcher can be added pushes managers toward an internal answer for either starting pitching needs or non-pitching needs, rather than treating the final month as a chance to retool the whole staff.

The other slot becomes a chess piece for roster construction, often tied to the daily grind: rest for a starter, a platoon advantage, late-season injury insurance, or a spark option if matchups demand it. Because the expansion is limited to two players, contenders may lean toward prospects who have already demonstrated the ability to perform at a major-league pace, even if they are not projected to become long-term cornerstones immediately.

For De Paula and Arias, being named in this “September call-up” category positions them as players whose teams could view as timely solutions rather than speculative lottery tickets. Whether a prospect actually gets activated depends on the last-mile evaluation of form in the days leading up to Sept. 1 and on what the parent club’s situation looks like at that time.

What to watch next is not just whether contenders announce promotions around Sept. 1, but how the additional players are deployed in the early days of the month. With only two roster additions available and the pitching constraint in place, the usage patterns can reveal what each club values most: bullpen matchups, bench performance, or the need to protect regulars from overuse.

In the final weeks, September roster management can become a quiet advantage. When teams get the right pair of additions under MLB’s limited expansion rules, they can protect their core while still keeping enough quality in reserve to sustain October-level performance. When they pick wrong, the cost is often paid quickly, because the season does not pause for experimentation.