https://blogs.fangraphs.com/strasburgs-return-and-a-thumbnail-guide-to-the-majors-most-improved-rotations/Article discusses how Stras has looked so far in the Spring and how, with Strasburg back, the Nats look like one of the most improved quality rotations (Boston's more improved, but coming off a low baseline)
On Strasburg:
On Tuesday, Strasburg took the mound for his first Grapefruit League appearance — against the Astros, coincidentally, albeit a much different team from the one he faced in the World Series, with Jose Altuve, Michael Brantley, Carlos Correa, and Yuli Gurriel the only starters in both games. The 32-year-old righty threw 38 pitches, had good command of a fastball that reportedly sat at 93 mph and ranged from 91 to 93 (he averaged 93.9 mph in 2019, via Statcast), and retired five out of the six batters he faced. He struck out four, including Correa looking at a high fastball to end the first, Kyle Tucker looking at a fastball in the second, and Gurriel check-swinging at a low curveball.
On the rotation
With Strasburg’s return on track, the Nationals project to have one of the majors’ top rotations, and one of its most improved relative to last year. That makes sense qualitatively and has quantitative grounding as well, particularly given the scarcity of four-win pitchers on the free-agent market or elsewhere. Strasburg averaged 4.2 WAR from 2012 to ’19 and ranked seventh among all pitchers in WAR during that span (33.2) despite reaching the 30-start threshold just three times and qualifying for the ERA title (162 innings) just four times. He topped out at 5.9 WAR in 175.1 innings in 2017 and had nearly as strong a season (5.6 WAR) in 209 innings in ’19.
Without Strasburg, the Nationals’ rotation slipped from second in the NL in WAR in 2019 (22.0) to 12th (3.0); within all of MLB, their ranking slipped from fifth to 23rd. By ERA, their NL rank slid from eighth (4.28) to 13th (5.09), and by FIP they fell from third (4.14) to tied for 13th (5.02). The slide wasn’t all on Strasburg: The FIPs of Max Scherzer and Aníbal Sánchez both increased by more than a full run, and Patrick Corbin’s rose by two-thirds of a run. With Joe Ross opting out of the season due to health concerns, the team couldn’t come up with anything close to a reliable fifth starter (a description that has only intermittently applied to Ross himself), as both Austin Voth and Erick Fedde were tarred and feathered, with FIPs in the mid-6.00 range. ...
But in 2021, Strasburg is back, Sánchez is gone, Jon Lester is here (now minus one of his parathyroid gland), and Scherzer and Corbin are presumably better rested after throwing over 200 innings between the regular season and postseason in 2019. The unit projects to rank fifth in the majors in WAR via our Depth Charts at 15.1 WAR, about two wins below a closely bunched top tier that includes the Padres, Dodgers, Mets, and Yankees, who range from 17.3 to 16.9.
