Red Sox Rookie Reliever Flying Under Radar As Valuable Bullpen Asset

Friday's outing was a departure from the norm for Boston's lefty flamethrower

Apr 21, 2024; Pittsburgh, Pennsylvania, USA; Boston Red Sox relief pitcher Cam Booser (71) pitches against the Pittsburgh Pirates during the fifth inning at PNC Park. Mandatory Credit: Charles LeClaire-USA TODAY Sports / Charles LeClaire-USA TODAY Sports

The Boston Red Sox bullpen wasn't up to snuff on Friday night.

Lucas Sims was the main culprit, allowing four earned runs on just 16 pitches in 1/3 of an inning pitched.

When lefty reliever Cam Booser took the mound in the top of the ninth, Boston trailed 5-3 and was still banking on late-game heroics.

Merely a few pitches later, the game became out of reach.

With an 0-1 count against Yordan Álvarez, Booser let a 95 MPH four-seamer drift into Álvarez's wheelhouse in the upper-middle portion of the plate. Álvarez, a lefty-on-lefty extraordinaire, smacked the pitch all the way to the right field wall for an RBI double (Luis García's baserunner).

Four pitches later, Yainer Díaz hit a 1-2 fastball from Booser over the Green Monster for a two-run homer, effectively ending the game.

With the Díaz blast, Booser had once again allowed his fastball to fall over the center of the plate, this one catching the top edge of the strike zone.

Ultimately, two mistake pitches from Booser led to three runs in a performance that was a complete abberation from what Booser has been this seaon for Boston -- an underrated and reliable reliever.

Before Friday's outing, Booser had allowed just two earned runs over his last 20 appearances dating back to June 6.

The 32-year-old rookie ranks in the 99th percentile (!) among Major League pitchers this season in chase percentage (36.5 percent), making his two ultra-hittable pitches to Álvarez and Díaz all the more uncharacteristic.

Booser also ranks well above average this season in virtually every advanced pitching metric outside of ground ball rate and extension. Relying on three pitches -- four-seam fastball, cutter, and sweeper -- Booser has displayed an impressive command of all three, even if he let two get away from him versus Houston.

Booser looked irate as the top of the ninth came to an end on Friday. A new observer of the Red Sox would have assumed that Booser was a struggling reliever leaving the mound after another failed outing.

Quite the opposite is true. Booser has been excellent for Boston this season, and it's easy to imagine him coming up huge in a playoff series.

Mere months removed from making his Major League debut, Booser has a lot to be proud of, and a lot more batters to defeat in 2024.

More MLB: Red Sox ‘Fully Convinced’ All-Star Infielder Will Return From Injury This Season