Diamondbacks call up Dennis Santana, designate Philip Abner for assignment in late roster tweak

The Arizona Diamondbacks made a bullpen adjustment on Aug. 16, selecting right-hander Dennis Santana from Triple-A Reno while designating left-hander Philip Abner for assignment in a corresponding move. The transaction keeps Arizona’s relief group in motion as the season heads into its final stretch, when late-inning innings often become the margin in close games.

According to the team announcement relayed by MLB Trade Rumors, Santana was chosen from Reno, giving Arizona another option in the late-inning mix. Calls from Triple-A at this point in the year typically reflect a need for fresh arms, matchup flexibility, or simply depth as managers manage workload and availability across a dense late schedule.

In the other half of the swap, Abner was designated for assignment. That step removes him from the 40-man roster and begins a short process in which the organization can trade him, release him, or, if he clears waivers, assign him to the minors depending on roster and eligibility rules. The move therefore indicates that the Diamondbacks were willing to change their internal bullpen pecking order.

For Diamondbacks fans, Santana’s selection is the clearer immediate storyline. A player moving up from Triple-A generally arrives with a specific role in mind, whether that is middle relief, a left-right matchup purpose, or innings coverage if other relievers are not available. What matters next is how quickly he gets into games and what leverage spots, if any, he handles once he is on the active roster.

Abner’s DFA also carries a separate kind of urgency. When a pitcher is designated for assignment, other clubs have an opportunity to claim him off waivers, which can result in an abrupt change of scenery. If he is not claimed, Arizona’s decision shifts to whether it views him as a long-term bullpen piece that can be reset in the minors or as someone the organization is moving on from.

This kind of “select and DFA” roster choreography is common in MLB, especially when teams are balancing the need for bullpen depth against the limits of roster construction. Even without additional context about performance or injuries, the structure of the transaction points to Arizona prioritizing a particular relief look for the near-term.

The next item to watch is whether Santana appears in the immediate game-day rotation for bullpen usage and, in Abner’s case, whether he attracts waiver interest. Those two outcomes will determine whether this was simply a one-day roster correction or the opening move in a broader bullpen reshaping for Arizona.

At this stage of the season, the smallest bullpen changes can have outsized ripple effects, from who pitches in the seventh and eighth innings to how often managers can avoid overworking their most trusted relievers. The Diamondbacks’ decision to swap Abner for Santana sets up the rest of the month as a period to watch for additional adjustments around the relievers’ usage patterns.