Can Corey Kluber turn back time with the Red Sox in 2023?

When the Boston Red Sox signed veteran right-hander Corey Kluber this off-season, there seemed to be a relative indifference towards the transaction that was shared by the media and fanbase alike. Kluber is still a solid pitcher who has been magnificent in the past, but many might feel like his best days are simply behind him now.

Could a magical 2023 season be in the cards for Corey Kluber with the Red Sox?

Kluber won 2 Cy Young awards (in 2014 and 2017) during his time with the Cleveland Indians (now the Cleveland Guardians). He posted a sub-2.50 ERA and tossed over 200 innings in both campaigns. In fact, Kluber logged over 200 innings in 5 straight seasons (2014-2018). He had a sub-3 ERA in 3 of those 5, and he never had higher than a 3.49 ERA in that 5-year stretch.

In aggregate, Corey Kluber's career numbers are very impressive. His 162-game averages per Baseball Reference for innings pitched (213), wins (15), ERA (3.31), and WHIP (1.11) point to a guy who has done more than enough to prove that he can be among the more effective pitchers in the game on a consistent basis.

So why was Kluber's signing hardly even discussed this off-season? Well, to start, he's in the back-9 of his career. He turns 37 this April, and he missed a substantial amount of time over the 3-year stretch leading up to last season due to a shoulder injury which ultimately required surgery in 2021. He's coming off a solid (but not spectacular) 2022 season in which he tossed 164 innings for the Rays (4.34 ERA; 1.21 WHIP).

In Kluber's defense, his peripherals from last year look a bit better than his surface-level stats. His FIP (3.57) and xERA (4.00) per Baseball Reference and Baseball Savant, respectively, point to a bit of bad luck pushing his ERA to a level that doesn't quite represent how effective he was.

Another advantage for Kluber in 2023 is his proven ability to be pitch effectively despite featuring below-average velocity. His 2022 average 4-seam fastball (88.9 mph) was a few ticks off what it was back in 2018 (92.0) per Baseball Savant, but he has an assortment of other pitches (cutter, curveball, sinker, changeup) that can all be utilized to keep hitters off-balance.

Corey Kluber has also continued to adjust his pitch-mix over the years. Coming into this season, his changeup could be a weapon to watch for. He only threw the changeup 6.6% of the time back in 2018, but in 2022 he increased its use rate to 10.3%. When he threw his change in 2022, opponents were left searching for answers and often not finding any (.226 BA, .258 SLG, 33.8% whiff rate).

It's tough to daydream about just how good Corey Kluber could be for the Red Sox if everything goes right without thinking of Rick Porcello. Rick had a solid career across 12 MLB seasons (4.40 ERA, 1.32 WHIP in 2096.1 innings), but he won the Cy Young award out-of-nowhere in 2016 with the Red Sox.

In his first season with the team in 2015, Porcello posted a 4.92 ERA across 28 starts (172.0 innings). But entering his 8th big-league season, he clearly managed to adjust and found the "secret sauce". In 2016, Porcello set career-highs in starts (33), innings pitched (223.0), ERA, (3.15), and WHIP (1.01).

And it's worth mentioning that Rick Porcello, who was only 27 years old in 2016, had already become more of a "pitcher" than a "thrower" by that point. His stuff didn't blow batters away, but his pitch-mix was very effective. The average velocity of his 4-seamer (92.2 mph) and sinker (90.1 mph) didn't light up the radar gun, but he only used these two pitches a combined 36.1% of the time per Baseball Savant.

It's hard to imagine Corey Kluber putting together anything less than a solid season for the Red Sox in 2023, matching what he did with the Rays in 2022. But who knows? Perhaps he can turn back the clock and give the Red Sox a magical season like Rick Porcello did in 2016.