With Paul DeJong suffering from a rib fracture and likely out until June, the St. Louis Cardinals needed somebody to step up at shortstop. DeJong had been the everyday shortstop, but he had not been producing at the plate. The 27-year-old has just an 84 wRC+ and 0.5 fWAR through his first 35 games. This is not great production, and nearly all of DeJong’s value had been created by his defensive abilities. Sosa, on the other hand, has hit the ball well and has provided the Cardinals with more production in just 21 games.
So far, Sosa is batting .382/.500/.500/1.000, giving him a 182 wRC+ and 0.7 fWAR in just 42 plate appearances. Additionally, Sosa is riding a six game hitting streak, while tallying multiple hits in four of those six games. This production has been important for a Cardinals lineup that is struggling to generate offense, and it has provided a threat from the bottom of the order. It is important that the Cardinals have been able to get production at the plate while DeJong has been injured.
Additionally, Sosa’s excellent defense has been comparable to DeJong’s defense at shortstop. This is another area where the impact of losing DeJong has been minimized as Sosa has been able to play strong defense since DeJong got hurt. On the season, Sosa has posted two outs above average, one defensive run saved, and a UZR/150 of 28.0. These numbers are actually better than DeJong’s -3 outs above average, one defensive run saved, and 4.5 UZR/150.
Additionally, Sosa’s sprint speed of 29.7 ft/s (98th percentile) is significantly better than DeJong’s sprint speed of 27.5 ft/s (63rd percentile). Thus, while DeJong has been hurt, Sosa has actually been better than him in every aspect of the game. This is unlikely to remain true as the season continues, but Sosa’s contributions since taking the job at shortstop have been important a Cardinals team with an inconsistent offense.
Despite Sosa’s success, there are some concerning numbers that suggest he cannot continue at this pace. To begin with, Sosa’s BABIP of .481 is completely unsustainable. However, his 90.2 mph average exit velocity is solid and even though his .373 xwOBA is significantly lower than his .443 wOBA, it is still strong. While this suggests that some kind of decline is likely to happen, Sosa’s minor league history suggests that he is not this good of a hitter.
Since reaching full-season ball, Sosa has never posted a wRC+ above 100. He has penty of success at the rookie level, but his production been near league average in each of his last few minor league seasons. Much of this is because of a limited walk rate which supresses his OBP even when he hits for a solid average. Since he has been unable to be an above league average hitter in the minor leagues, it should not be expected that he will be an above league average hitter in the major leagues. On the defensive side, though, he should continue to play well. He has always been given higher marks with the glove than with the bat, and this should allow him to retain some value for the Cardinals, especially given his speed.
It is unlikely that Sosa will continue to produce like this at the plate. However, his production through 21 games has been crucial for the Cardinals’ lineup, and it has helped the team by providing a threat from the bottom of the order. This, along with his defensive abilities, has been important for a Cardinals team that has struggled to string wins together. This success may not last all season, but it has come at the right time, and Sosa has been a key member of the team since being pressed into action by DeJong’s injury.