Kenneth Dieter Waldichuk...Graduated from University City High School (Calif.)...Attended Saint Mary's College (Calif.)...Won the West Coast Conference ERA title (2.05), earning 2018 Collegiate Baseball Second-Team All-American honors.
2025
Threw three scoreless innings on June 22 vs. Inland Empire in his return to the mound...Missed the beginning of the season while continuing to rehab from Tommy John surgery, but appeared in 17 games (16 starts) between Single-A Stockton and Triple-A Las Vegas, striking out 68 batters in 54 innings with an 8.17 ERA (84 ER/141 IP)... Designated for assignment by the Athletics following the conclusion of the season, Dec. 22.
2024
Was placed on the 60-day injured list Feb. 14 with a strained left elbow...Had “Tommy John” surgery on his left elbow on May 15...the surgery was performed by Dr. Neil ElAttrache at the Cedars-Sinai Kerlan-Jobe Institute and involved a flexor tendon repair and a UCL reconstruction with internal brace procedure...Missed the entire season.
2023
Spent the entire season with the A’s, working as a starter, reliever and opener…went 4-9 with one save, a 5.36 ERA and .840 opponents OPS in 35 games, including 22 starts...Struck out 132 batters, which tied for fifth most in Oakland history by a rookie…surrendered 24 home runs, which tied for third most...Ranked fourth among Major League rookies in strikeouts and fifth in innings pitched (141.0)…was also second runs allowed (93) and walks (71), tied for second in hit batters (9), third in hits (149), tied for third in home runs and tied for fourth in losses (9)...His 71 walks tied for 10th most in the majors among all pitchers...Based on a minimum of 140 innings pitched, he had the second highest opponents on-base percentage in the majors (.360), third lowest strikeout-to-walk ratio (1.86), fourth highest OPS (.840), fifth most pitches per inning (18.1), seventh highest ERA and ninth highest slugging percentage (.480)...Using the 140 innings pitched minimum, he had the seventh highest OPS in Oakland history and the eighth highest ERA and slugging percentage...Led the A’s in runs and walks...Went 1-4 with a 7.46 ERA and 1.012 opponents OPS in 12 games, including 10 starts, in April and May…then compiled a 3-5 record with a 4.18 ERA and .732 opponents OPS over his final 23 games, including 12 starts…had an ERA above 7.00 in each of the first two months (7.26 in April, 7.78 in May) and under 5.00 in the last four (4.60 in June, 4.91 in July, 3.68 in August, 4.00 in September)...Went 2-5 with a 5.33 ERA and .879 OPS in his 22 starting assignments and his 15 no decisions tied for fifth most in the majors among starters…the no decisions tied the Athletics record for most by a starting pitcher in a season…shares the mark with Ron Darling, who went 5-9 in 29 starts in 1993…left with the lead and was in position to win in five of his no decisions…made 20 traditional starts and two as an opener...Was 2-4 with a 5.45 ERA and .732 OPS in 13 relief appearances…tossed at least two innings in 10 of his relief appearances, including 4.0 or more four times…first batters faced were 5-for13 (.385) and he allowed 1-of-2 inherited runners to score...Allowed a .271 opponents batting average, which included a .269 (29-for-108) mark and .949 OPS against left-handed hitters and .271 (120-for-442) with a .813 OPS against right-handers…17 of the 29 hits he allowed to lefties were for extra bases...Opponents hit .259 with runners in scoring position and were 2-for-20 (.100) with a double, a grand slam and four walks with the bases loaded...As a starter, he had a .229 opponents batting average and .764 OPS the first time through the order, .280 and .921 the second time and .330 and 1.024 the third time…combined for a 2.93 ERA over innings 1-3, had a 10.56 ERA in the fourth inning and a 6.26 ERA from the fifth inning on...Was 1-3 with a 4.46 ERA in 16 games at home, 3-6 with a 6.17 ERA in 19 games on the road…is now 3-4 with a 4.29 ERA in 19 career games in the Coliseum, 3-7 with a 6.19 ERA in 23 games on the road...Posted a 0-4 record, a 7.15 ERA and .956 opponents OPS in 13 day games…went 4-5 with a 4.68 ERA and .791 OPS in 22 night games...Was 2-6 with a 6.63 ERA and .950 OPS in 21 games before the All-Star Break, 2-3 with a 4.04 ERA and .714 OPS after the break...Collected three of his four wins against American League Central teams and was 3-0 with a 4.56 ERA in six games, including five starts...Went 1-3 with a 7.23 ERA in 11 games on four days rest, 3-6 with a 4.57 ERA in his other 24 appearances...Held the opponents leadoff hitter to a .227 batting average but the five hitter batted .365…did not surrender a home run to the clean-up hitter...Committed four errors, which tied for second most in the majors among pitchers…had three pickoffs, which tied for 11th most...The A’s were 9-13 (.409) in his starting assignments.
2022
Made both his Triple-A and Major League debuts in 2022…began the season in the New York Yankees organization, was dealt to the A’s at the trading deadline and joined Oakland in September for his big league debut…went 2-2 with a 4.93 ERA and .781 opponents OPS in seven games, all starts...Struck out 33 batters in 34.2 innings and walked 10 for a strikeout-to-walk ratio of 3.30...Allowed a .244 opponents batting average, which broke down to .138 (4-for-29) with a .366 OPS against left-handed hitters compared to .275 (28-for-102) with an .897 OPS against right-handers…surrendered 17 of his 18 extra-base hits and issued nine of his ten walks to right-handed hitters...Yielded a .288 batting average and .843 OPS the first time through the order, .196 with a .650 OPS the second time and .238 with a .923 OPS after that...Was 2-1 with a 3.63 ERA and .653 opponents OPS in three starts in the Coliseum, 0-1 with a 6.23 ERA and .884 OPS in four starts on the road…however, surrendered four of his five home runs in Oakland...Had a 7.52 ERA and .962 opponents OPS in odd-numbered innings, a 1.26 ERA and .523 OPS in even-numbered innings…did not allow a run in the fourth inning (6.0 IP)...The first two hitters in the batting order combined for a .371 batting average against him but he held the three through nine hitters to a .198 average...Opponents were 0-for-12 on an 0-2 count...Tossed five innings or fewer in five of his seven starts...Combined for a 6-4 record, a 2.84 ERA and .644 opponents OPS in 21 starts with Double-A Somerset, Triple-A Scranton/Wilkes-Barre and Triple-A Las Vegas...Struck out 137 batters in 95.0 innings, an average of 12.98 per nine innings…walked 36 for a strikeout-to-walk ratio of 3.81...Matched his Minor League best in wins and starts...His average of 12.98 strikeouts per nine innings was second best among Double-A and Triple A pitchers with 90 or more innings pitched and 10th best among all Minor Leaguers…also ranked 11th among Double-A and Triple-A pitchers in ERA and 16th in opponents OPS, batting average (.211) and slugging percentage (.343)...Represented the American League in the All-Star Futures Game...Allowed a .211 opponents batting average, which broke down .168 (16-for-95) with a .528 OPS against left-handed hitters compared to .227 (58-for-255) with a .687 OPS against right-handers...Held the opposition to a .188 average with runners in scoring position...Was 6-2 with a 1.99 ERA and .568 opponents OPS over his first 14 starts through July 4…then went 0-2 with a 5.00 ERA and .813 OPS over his final seven minor league starts...Was 4-0 with a 1.91 ERA and .547 opponents OPS in nine starts on six days rest or more, 1-4 with a 4.25 ERA and .774 OPS in 10 starts on five days rest or fewer...Had a 5.14 ERA and .876 opponents OPS in the first inning, a 2.19 ERA and .577 OPS from the second inning on…yielded five of his 10 home runs in the first inning...Allowed a .135 batting average with two strikes...His teams were 9-2 in his no-decisions and had a 15-6 (.714) record in his starting assignments…tossed five innings or fewer in 18 of his 21 starts…allowed six hits or fewer in all 21 starts and two runs or fewer 16 times…had more strikeouts than innings pitched 17 times...Was rated as the A’s fifth-best prospect by Baseball America following the season but was listed as number two by MiLB.com...DAY-BY-DAY: Began the year at Double-A Somerset and did not allow a run in each of his first two starts on April 9 at Reading and April 16 against Erie…tossed five innings for the win in each outing…finished April 2-0 with a 1.45 ERA in four starts…then went 2-1 with a 1.33 ERA in four starts in May…logged five scoreless and hitless innings on May 8 against New Hampshire and struck out a Minor League career high 12 batters in a 3-2 win…yielded a minor league season-high six hits in a 12-8 win at Altoona, his final Double-A start…was 4-0 with a 1.26 ERA and .479 OPS in six starts at Somerset when he was promoted to Scranton/WilkesBarre on May 17…had a no decision in his Triple-A debut on May 22 at Worcester (5.1 ip, 3 h, 1 r, 1 er, 2 bb, 9 so) and then suffered his first loss of the season on May 28 against Jacksonville, a 3-0 decision…tossed six innings and struck out 11 in an 8-4 win at Syracuse on June 11…it was his second 10-strikeout game of the season and the eighth of his career…had season highs in walks (4) and runs (5) in a 7-6 loss to Rochester on June 17…matched his season-high with four walks June 29 against Buffalo…allowed four runs on five hits in a season-low two innings in an 8-3 loss at Worcester on July 10…recorded the save for the American League in the All-Star Futures Game on July 16 at Dodger Stadium…entered the game with two outs in the bottom of the seventh and got Jackson Chourio to fly out to preserve a 6-4 win…made two more starts for Scranton/Wilkes Barre on July 26 and 31 at Rochester and was 2-3 with a 3.59 ERA and .695 OPS in 11 starts when he was traded to the A’s on Aug. 1 with Luis Medina, JP Sears and minor leaguer Cooper Bowman for Frankie Montas and Lou Trivino…took the loss in his first start with the Aviators on Aug. 6 against Reno and then had three straight no-decisions (2.35 ERA…went 0-1 with a 3.38 ERA and .744 OPS in four starts with Las Vegas… was selected by Oakland on Sept. 1 and made his Major League debut that day at Washington…had a no decision in the A’s 7-5, ten-inning loss and walked a career-high four batters in 4.2 innings…issued just six free passes over his final six starts and 30.0 innings…became the 57th pitcher in Oakland history to start in his ML debut, the fourth in 2022…struck out Luke Voit looking in the first inning for his first strikeout…took the loss in his second and fourth starts and was 0-2 with a 7.13 ERA and .908 OPS over his first four starts through Sept. 18… then went 2-0 with a 2.65 ERA and .617 OPS over his final three starts…allowed a career-high five-runs on a career-high eight hits in five innings at Texas on Sept. 13 but had a no-decision in an 8-7 loss…left with a 7-5 lead but the bullpen blew the save…also allowed five runs in just 2.2 innings in his next start on Sept. 18 at Houston for the loss…picked up his first Major League win in a 10-4 A’s victory on Sept. 24 against New York (NL), despite allowing four runs in five innings…struck out a career-high eight batters and allowed just one run in five innings on Sept. 30 at Seattle but had a no-decision in the A’s 2-1 loss…tossed a career-high seven scoreless innings and logged a career-high 100 pitches for the win in his final start, a 3-2 A’s victory over Los Angeles (AL) in the final game of the season…finished the season with an 11.0-inning scoreless streak.
2021
Combined with High-A Hudson Valley and Double-A Somerset to go 6-3 with a 3.03 ERA in 23 games, including 21 starts…struck out 163, which tied for fourth most in the minors…led Yankees minor leaguers in strikeouts, ranked second in opponents batting average (.193), fourth in ERA and innings pitched (110.0 ip) and tied for fourth in games started…allowed three runs or fewer in 18 of his 21 starts, including two or fewer 14 times…began the season with Hudson Valley, posting a career-long 30.2 scoreless inning streak over seven starts with the Renegades… was promoted to Somerset on June 15, going 4-3 with a 4.20 ERA in 16 games, 14 starts…ranked third in the Double-A Northeast in strikeouts (108)…following the season, was named by Baseball America as the No. 10 prospect in the Yankees organization…was named a MiLB.com Organization All-Star.
2020
Did not pitch due to the pandemic.
2019
Made his professional debut with Rookie-level Pulaski, going 0-2 with a 3.68 ERA in 10 starts…struck out 49 and walked just seven in 29.1 innings…also made one postseason start and had a no decision, tossing 4.2 scorless innings, allowing one hit and striking out nine in a 6-0 win over Burlington on Aug. 31.
