On 29 December 2020, Darvish along with personal catcher Víctor Caratini were traded to the San Diego Padres in exchange for pitcher Zach Davies and four prospects.[91] In his first year with the Padres, Darvish posted an 8–11 record with a 4.22 ERA and 199 strikeouts in 1661⁄3 innings. He was also named to his fifth All-Star team.
Named the ace of the Japanese national team by manager Senichi Hoshino in the 2008 Beijing Olympics,[92] Darvish took the hill in Japan's first game of the preliminary round against Cuba on 13 August, but was charged with the loss after giving up four runs in four innings.[93] The subpar outing caused Hoshino to lose faith in him and scratch Darvish from the semi-finals that he had penciled him in for, sending Darvish to the mound only in situations that would have no bearing on Japan's fate in the tournament. Darvish started the last game of the preliminary round against the United States on 20 August and was brought in to mop up after the U.S. had taken a decisive lead in the bronze medal match, finishing the tournament 0–1 with a 5.14 ERA (albeit with 10 strikeouts in seven innings pitched).
Darvish pitched in the 2009 World Baseball Classic as the de facto ace of the Japanese national team,[94] starting the opening game against China on 5 March. He pitched four innings, allowing one walk and no hits and striking out three as Japan beat China, 4–0. However, pitching in a Major League stadium for the first time in his career, he struggled in his second outing of the tournament against South Korea on 17 March, throwing five innings and giving up three runs (two earned) on four hits and a walk and ultimately being charged with the loss.[95] His first career save would follow six days later, when he pitched the final inning of the semi-finals against the United States, yielding no runs and a single and striking out two as Japan won 9–4.[96]
Darvish came on in relief in the bottom of the ninth inning of the championship game against South Korea with Japan leading 3–2. He struck out his first batter, walked the next two, struck out his next, and then gave up a tying two-out single before finishing the inning with another strikeout. However, Japan scored two runs in the top of the tenth inning to regain a 5–3 lead, and after giving up a leadoff walk in the bottom of the inning, Darvish retired the next three batters (striking out two of them) to clinch Japan's second consecutive tournament title.[97] In the WBC he finished at 2–1 with a 2.08 ERA and 20 strikeouts in 13 innings. He recorded a career-high 99 mph when he worked in relief at the WBC.[98]
Darvish, along with Ichiro Suzuki and Daisuke Matsuzaka, chose not to play in the 2013 World Baseball Classic.
Darvish is a right-handed pitcher who throws from a three-quarter arm slot in a drop-and-drive motion.[99] He has a large frame for a pitcher, listed at 6 ft 5 in and 220 lb. Darvish throws a four-seam fastball which averages 93–95 mph (tops out at 99 mph[100]),[101][102][103] as well as a hard slurve (slider) in the low 80s with a sharp break.[101][104][105] He complements these two with a wide repertoire of secondary pitches, including a two-seam fastball (also described as a shuuto),[106] a cutter, two curveballs, a splitter, and an occasional changeup.[107] Darvish has a "fast curve" and a "slow curve", the former averaging about 80 mph and the latter about 71. The slow curve is almost exclusively used in no-strike and 1-strike counts, while the fast curve is mostly used in 2-strike counts.[108] Some professional scouts consider Darvish to have the best repertoire of quality pitches, including the best slider, in all of Major League Baseball.[101] In August 2019, Darvish learned a knuckle curve from Cubs teammate Craig Kimbrel and began using the pitch.[109]
Advance scouting on Darvish is made difficult by his tendency to change his most frequent pitch sequences over time.[110]
While Darvish uses both the set, or "stretch" position and the windup, he has been noted for pitching exclusively from the stretch at times, even when there is no one on base.[111] While pitching from the windup is generally thought to add velocity to pitches, the set position allows pitchers more control over baserunners.[112] In Darvish's case the set position often is used as a way of keeping his delivery in sync and consistent.[111]
Prior to the 2006 season Darvish's "go-to" pitch was a screwball, and he tends to rely more on his off-speed pitches than his fastball. After injuring his shoulder in an exhibition game start against the 2006 World Baseball Classic Japanese national team in February 2006, because of the strain the screwball had gradually been putting on his shoulder, he took the pitch out of his in-game repertoire and worked to develop his splitter until it became an equally effective pitch that would replace the screwball. He also has succeeded in increasing his fastball velocity from year to year.[citation needed]
In 2019 season alone, he used 10 different pitches: Cutter with two different movements, four seam and two seam fastballs, slider, splitter, normal and slow curveballs, knuckle curve and a changeup. In 2020, he revealed on Twitter that he learnt a 'supreme pitch', which is a hybrid between a splitter and two-seam fastball. This pitch can reach 93 mph.[113]
Yu Darvish also has a few ways to learn new pitches to add to his deep pitching arsenal. One of his favorites was to use it in game without knowing, which forces him to adapt quickly.