Diaz’s performance in 2023 wasn’t as dominant due to his struggles with first-pitch strikes (55%) and his walk rate, which remained largely unchanged from 2022 (4.8 in 2023 compared to 4.7 in 2022). Despite limiting batters to a .186 average against him—.197 vs. righties and .177 vs. lefties—Diaz had solid results early on. Through the first five months, he posted a 2.18 ERA, 78 strikeouts, six wins, and 35 saves in 57.2 innings. However, late in September, he struggled in back-to-back outings, giving up seven runs and eight baserunners in one inning, followed by five walks and one run in his last two innings.
In 2023, Diaz continued to have trouble finding the strike zone, with a 54% first-pitch strike rate. His walk rate increased to 5.0 batters per nine, and his strikeout rate dropped sharply (8.8 K/9 compared to 11.5 in 2022). May and August were especially rough, with ERA numbers of 8.68 and 7.00, respectively, and WHIP figures of 1.929 and 1.333. However, over his other 38 innings, he posted a 2.13 ERA, a 1.132 WHIP, and 35 strikeouts with 19 saves.
Diaz’s average fastball velocity dropped to 94.1 mph, the lowest in three years. He relies on a four-seam fastball (.194 BAA) and a slider (.214 BAA), generating a solid amount of infield flies (18.6%) by pitching up in the zone (47.6% fly-ball rate).
Fantasy Outlook: Despite a drop in fastball velocity, Diaz still boasts two difficult-to-hit pitches, even though his command remains inconsistent. With 75 saves in the last three seasons, he has a strong chance of bouncing back, making him a decent option for saves, with the hope that his control improves. He offers good value at his current price.
Top Reds Handcuff – Tony Santillan, CIN
Santillan’s 2023 season was marred by health issues, leading to a rough stint at AAA (7.88 ERA, 2.063 WHIP, 40 strikeouts in 32 innings). His control was a major issue, walking 7.9 batters per nine innings, and he allowed five home runs. Injuries to his back and hamstring kept him out for a period, and the Reds released him in late August.
In 2022, Santillan had a much stronger performance at AAA, posting a 3.49 ERA with a WHIP of 1.422 over 38.2 innings. He recorded 53 strikeouts and 16 saves. When called up to the majors in mid-July, his control (2.7 walks per nine) was better than expected, and he limited opponents to a .186 batting average with a fantastic strikeout rate (13.8 K/9). Santillan finished the season with a solid 3.00 ERA and 1.000 WHIP.
His average fastball velocity of 97.3 mph was the best of his career. He relied heavily on his four-seam fastball (.203 BAA), throwing it 60.3% of the time, while his slider (.163 BAA) was his only other pitch.
Fantasy Outlook: Santillan’s major league success is limited to a small sample, and his minor league history suggests command issues. While his fastball offers a velocity advantage, he needs to pitch ahead in the count to make his slider more effective. For now, he’s a player to monitor until he proves last season wasn’t an outlier.