This is MLB's ultimate boom-or-bust rotation

The Rangers’ rotation has gone through a dramatic overhaul this offseason, with Texas doling out more than $260 million in guaranteed money to bring in five starters.

The Rangers posted the sixth-worst rotation ERA (4.63) in the Majors last season, and Texas starters combined for just 5.8 WAR (per FanGraphs), MLB’s fifth-lowest total, so it’s not exactly a surprise that the club decided to focus on improving its starting staff. But the extent of the remodel is striking.

Texas made one of the most shocking moves of the offseason when it landed two-time Cy Young Award winner Jacob deGrom on a five-year, $185 million deal early in free agency. In addition, the Rangers brought back Martín Pérez via the $19.8 million qualifying offer, signed free agents Andrew Heaney (two years, $25 million) and Nathan Eovaldi (two years, $34 million) and traded for Jake Odorizzi. They also have holdover Jon Gray, who joined the team on a four-year, $56 million contract after 2021.

This would be an interesting experiment regardless of which arms the Rangers chose to pursue, but the pitchers they settled on make this one of the most intriguing situations in all of baseball entering the 2023 season.

deGrom, Pérez, Heaney, Eovaldi, Odorizzi and Gray are all 31 or older, with an average 2023 seasonal age of almost 33. Most have significant injury histories. In fact, all but Pérez spent time on the injured list in 2022.

However, this group also offers substantial upside. As a result, there appears to be a Texas-sized gap between the best- and worst-case scenarios involving the Rangers’ rotation in 2023. Granted, you can say that about many starting staffs. But when it comes to this Rangers group, you don’t have to squint that hard to see either scenario playing out.

Here’s a closer look at MLB’s ultimate boom-or-bust rotation.

Best case: MLB’s best rotation?

FanGraphs’ Depth Charts projections provide a good look at how the Rangers’ rotation might stack up against some of MLB’s other elite staffs if everything goes right.

In terms of projected starting pitcher WAR in 2023, FanGraphs has the Yankees, with ace Gerrit Cole joined by new addition Carlos Rodón and returning hurlers Luis Severino, Nestor Cortes and Frankie Montas, at No. 1. The Brewers and Braves are third and fourth, respectively, while the Mets and Phillies are tied for fifth.

In second? None other than the Rangers.

Projected SP WAR in 2023, per FanGraphs Depth Charts

• Yankees: 16.7
• Rangers: 15.6
• Brewers: 15.0
• Braves: 14.4
• Mets: 13.8
• Phillies: 13.8

And yet, these projections arguably don’t even represent the best-case scenario for Texas’ rotation. While some of the innings projections are optimistic -- FanGraphs has deGrom, Gray and Heaney combining for nearly 500 frames -- the performance estimates are a bit conservative, as most projections tend to be.

For example, Eovaldi (projected for 2.3 WAR) and Pérez (1.8) were much more valuable in recent seasons, with Eovaldi recording 5.7 WAR in 2021 and Pérez producing 3.8 WAR last year. deGrom (projected for 5.5 WAR) was a 6.9-WAR pitcher in 2019, his last full, healthy season.

If all three can replicate those campaigns in 2023, they could be worth anywhere from 5.0 to 7.0 more combined WAR than FanGraphs is projecting them to produce, perhaps putting the Rangers in position to have the best rotation in MLB.

Worst case: Injuries and regression galore

One doesn’t need to look too far into the past to see the worst-case scenario for this group.

Just last season, deGrom, Heaney, Eovaldi and Gray combined to make 69 starts (71 total appearances) and produce 6.1 WAR. If that happens again, the Rangers are going to have to rely on Odorizzi, Dane Dunning, Cole Ragans and/or Glenn Otto -- a quartet that combined for 2.3 WAR over 87 starts in 2021 -- more than they’d probably like.

Then there’s Pérez, who experienced an out-of-nowhere breakout at the age of 31 in 2022, posting a career-best 2.89 ERA with 3.8 WAR in 32 starts. From 2012-21, Pérez had a 4.71 ERA and 11.6 WAR over 1,102 2/3 innings.

It’s not far-fetched to think Pérez will revert back to that level in 2023. If that happens, and deGrom, Heaney, Eovaldi and Gray do what they did last year, we could be looking at a situation in which the Rangers get less than 8.0 WAR combined out of those five pitchers.

Middle case: Some hits, some misses

The third (and most likely) scenario for the Rangers’ rotation is that some of their moves work out, while others don’t.

It’s not realistic to expect any rotation to stay healthy all season, and that’s especially true for this group. There are also some question marks from a performance standpoint. deGrom is a good bet to contend for the AL Cy Young Award if he makes 30-plus starts, and Eovaldi and Gray are fairly predictable at this stage of their careers, but Pérez and Heaney are complete wild cards.

We've already covered the stark contrast between Pérez's 2022 performance and his track record up to that point. Heaney is in a similar boat. He entered last season with a lifetime 4.72 ERA over his first eight seasons, including a 5.83 ERA for the Angels and Yankees in 2021, but thrived in the Dodgers' ecosystem a year ago.

The left-hander finished 2022 with personal bests in ERA (3.10), K/9 (13.6) and K/BB ratio (5.79), albeit in only 72 2/3 innings. Unlike Pérez, who has made at least 29 starts in a season four times, Heaney has made more than 23 starts only once (2018).

While this middle scenario would be better than the worst case, it would likely still go down as an “L” for the Rangers.

Though Texas has been busy on the rotation front this offseason, the club hasn’t done anything to address an offense that placed 12th in MLB in runs scored (707) and tied for 19th in wRC+ (98). Nathaniel Lowe (141), Corey Seager (117), Adolis García (112), Marcus Semien (107) and Mitch Garver (101) were the only Rangers who tallied at least 100 plate appearances and had a wRC+ of 100 (representing league average) or better in 2022.

As it stands, the Rangers are poised to head into the spring with the likes of Leody Taveras (93 wRC+ in 2022), Bubba Thompson (77), Brad Miller (69) and Josh Smith (68) vying for regular playing time, which puts a lot of pressure on No. 1 prospect Josh Jung (81) to break out.

Given their offensive limitations, the Rangers need this rotation experiment to be a rousing success. Otherwise, they might be staring at their seventh straight year without a postseason appearance.