Red Sox rotation filled with question marks ahead of 2023 season

No MLB starting rotation has a wider range of potential outcomes than the Boston Red Sox staff.

There is no shortage of talent in the Red Sox rotation. Seven-time All-Star Chris Sale leads the group and is followed by two-time Cy Young award winner Corey Kluber, dominant reliever-turned-started Garrett Whitlock, and former top prospect Brayan Bello. Nick Pivetta is a workhorse at the tail end of the rotation and James Paxton's ceiling is sky-high when he's healthy.

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The problem is all of those pitchers have low floors. Sale and Paxton have made a combined 17 starts since the end of the 2019 season due to injuries. Kluber is turning 37 years old and is no longer his Cy Young self. Whitlock is unproven as a starter. Bello still has plenty to prove as a big-leaguer and Pivetta can't be counted on as anything more than a No. 5 starter.

So, what does this all mean for the Red Sox in 2023? What are the best and worst-case scenarios for each of Boston's starters? Here's a closer look at the high-risk, potentially high-reward group.

Chris Sale, LHP

2022 stats: 0-1, 3.18 ERA, 1.059 WHIP, 1 BB, 5 SO, 5.2 IP (two starts)

Red Sox fans will be watching Sale's starts with one eye open going forward. The veteran southpaw has made only 11 starts since the conclusion of the 2019 season due to injury. At this point, many believe it's simply a matter of when -- not if -- he'll get hurt again. But on the off chance he stays healthy, there's no reason he shouldn't rediscover his ace form. The 33-year-old, who was a perennial Cy Young candidate from 2012-18, looked sharp in his first spring training start. The stuff is still there. The only question is whether his body is capable of holding up for an entire season.

Best-case scenario for 2023: Sale finally avoids the injury bug and reestablishes himself as Boston's clear-cut ace.

Worst-case scenario for 2023: Yet another injury setback prevents Sale from making an impact and leaves his Red Sox future in doubt.

Corey Kluber, RHP

2022 stats: 10-10, 4.34 ERA, 1.213 WHIP, 21 BB, 139 SO, 164.0 IP (31 starts with Tampa Bay Rays)

The Red Sox signed Kluber to a one-year, $10 million contract in December. While his Cy Young days are most likely behind him, the soon-to-be 37-year-old showed last season with the Rays he still has plenty left in the tank. The biggest takeaways from his bounce-back campaign were his league-best walk rate (1.2 BB/9) and his 164 innings pitched. As long as he can stave off injury in 2023, he'll be a key contributor for Boston. 

Best-case scenario for 2023: Kluber shows flashes of his Cy Young days and forms a scary 1-2 punch at the top of the rotation with Sale.

Worst-case scenario for 2023: Kluber shows his age and fails to give the Red Sox consistency at the front of the rotation.

Garrett Whitlock, RHP

2022 stats: 4-2, 3.45 ERA, 1.021 WHIP, 15 BB, 82 SO, 78.1 IP (31 games, nine starts)

The Red Sox are betting on Whitlock being as effective as a starter as he's been as a reliever over the last couple of seasons. That's a risky bet to make, but it's understandable why they're thinking that way. When he's on, Whitlock might have the best stuff on the pitching staff outside of a healthy Chris Sale. The problem is Whitlock hasn't been healthy himself. He underwent season-ending hip surgery last year and might not be ready for Opening Day. That's a cause for concern as Whitlock will be one of Boston's most important players in 2023.

Best-case scenario for 2023: Whitlock's hip injury is a non-factor and his dominance as a reliever translates to a full-time starting role.

Worst-case scenario for 2023: The decision to convert Whitlock from a reliever to a starter backfires as he struggles to replicate his production out of the bullpen, or his hip injury keeps him sidelined for an extended period of time.

Brayan Bello, RHP

2022 stats: 2-8, 4.71 ERA, 1.779 WHIP, 27 BB, 55 SO, 57.1 IP (13 games, 11 starts)

Bello's first stint in the majors was a mixed bag. There were growing pains in his first few appearances but with time, the Red Sox' former top prospect provided reasons to be encouraged about his potential as a full-time member of the rotation in 2023. Don't let the high ERA and WHIP numbers above fool you. He allowed only one earned run over his final 23 1/3 innings of the season and his 2.94 FIP suggests he was extremely unlucky. Bello could wind up being the star of the Red Sox' rotation this season, though it's certainly worrisome that he's already dealing with a forearm issue.

Best-case scenario for 2023: Bello shows why was ranked as the organization's top pitching prospect and gives the Red Sox much-needed stability in the middle of the rotation.

Worst-case scenario for 2023: The growing pains continue and Bello can't be counted on to take the ball every fifth day, or his forearm injury causes him to miss a significant chunk of the season.

Nick Pivetta, RHP

2022 stats: 10-12, 4.56 ERA, 1.38 WHIP, 73 BB, 175 SO, 179.2 IP (33 starts)

Pivetta is far from an ace, but the 30-year-old was a workhorse for a Red Sox rotation that dealt with its fair share of injuries over the course of the 2022 season. He led the majors with 33 starts while leading the team in strikeouts and innings pitched. The problem for Pivetta continues to be command and keeping the ball inside the ballpark. Those issues could force Pivetta into a relief role in 2023, though he has adamantly stated his desire to start. If the rotation stays healthy -- a major "if" -- Pivetta might be the odd man out.

Best-case scenario for 2023: Pivetta once again steps up as a workhorse at the back end of the rotation and lowers his ERA to around 4.00.

Worst-case scenario for 2023: Pivetta is the odd man out in the rotation and struggles to adjust to a relief role.

James Paxton, LHP

2022 stats: N/A

Paxton has made only six starts since the end of the 2019 season due to an assortment of injuries, including a torn lat suffered last year while recovering from Tommy John surgery. It took him less than two innings in his first spring training start of 2023 to have a setback, this time a hamstring strain that is expected to keep him out through Opening Day. The 34-year-old's $ 4 million deal for this season could be a steal for Boston if he can stay on the field, but he has yet to prove capable of doing so.

Best-case scenario for 2023: Paxton stays healthy and performs like his pre-injury self while giving the Red Sox 150+ innings.

Worst-case scenario for 2023: Another season spent recovering from injury.