The initial plan was for Daniel Harper to start the season with Double-A Reading, but injuries interrupted the plan throughout the 2025 season. After just one outing with Reading, Harper was placed on the IL and would stay there until mid-June and then returned to the Fightins for just over two weeks and was then moved up a rung to Lehigh Valley. After just three more appearances, Harper was again back on the IL and spent another three weeks there until returning to Lehigh Valley and finishing the season. To help get the 26-year-old more work the Phillies sent him to the Arizona Fall League.

Minor-league record and level-by-level performance

Harper’s professional record through the 2025 season shows heavy usage out of the bullpen. His 2024 season split between High-A Jersey Shore and Double-A Reading produced a combined 51.0 innings, a 2.82 ERA, 61 strikeouts and 20 walks with an overall 1.16 WHIP, including a 2.08 ERA, 38 strikeouts and a 0.96 WHIP in 26.0 innings at High-A, but those numbers bumped up to 3.60 ERA, but his strikeouts-per-nine innings ration did move up to just below a strikeout per inning. Harper’s 2025 Triple-A stint with Lehigh Valley was difficult, as he allowed 18 earned runs in 15.1 innings for a 10.57 ERA with a 1.89 WHIP while being charged with five home runs, nine walks and 13 strikeouts. Overall in the minors, Harper is 7-7 with a 4.49 ERA in 99 relief appearances. In the AFL, Harper has logged just 1.1 innings of work over two appearances with the Surprise Saguaros.

Sabermetric profile and key peripherals

Using his organizational totals, Harper’s strikeout and control profile reads as an above-average ability to miss bats paired with inconsistent control: his career minor-league K/9 sits at 9.2, his BB/9 is at 4.6 and his career K/BB ratio is right around 2.0. Those numbers explain the profile of a power‑oriented reliever whose effectiveness is limited at times by free passes and elevated run rates, which explains his career 4.49 ERA and 1.47 WHIP in the minors.

Scouting summary: strengths and weaknesses

Harper profiles as a power reliever with an arm slot and frame that project well for late-inning usage, and his ability to generate swings-and-misses – reflected in a near-9.2 K/9 rate – is his primary strength. His principal weakness is control, which has led to an elevated WHIP and ERA. Those issues have also led to an exposure to long balls and higher contact rates, especially during his 2025 Triple-A exposure. While the 2025 AAA results indicate he still needs cleaner command and better sequencing against more experienced hitters, the Phillies will have to determine how much the injuries – which were undisclosed as to exactly what the injuries were – contributed to his struggles at Triple-A.

Projection and immediate outlook

Harper projects in the near term as a high‑variance bullpen arm who profiles as middle‑to‑low leverage depth for the big-league club. If he can reduce his walk rate and limit hard contact at Triple-A – and his assignment to the AFL suggests that the Phillies believe he can – Harper will have an opportunity to build consistency before potential major-league consideration.