FORT MYERS, FLA. – Bailey Ober worked up a major sweat as he threw in the bullpen at Hammond Stadium on Tuesday. He requested a towel several times to wipe his brow, his right hand and even the baseball.

After his bullpen session, he headed for the gym for more sweating. He has a workout plan, designed by former Twins trainer Jenn Reiner-Marcello that helps with maintenance and recovery. He's even tweaked his diet. When his fastball topped out at 94.8 miles per hour on Saturday against Philadelphia, it was a sign to him that he's on the right path.

"Just trying to do everything I possibly can and leave everything out there," he said. "Doing everything I can."

Whatever it takes to improve, Ober seems to be doing it. The 28-year-old righthander is on the right track after going 8-6 with a 3.43 ERA last season while throwing a career-high 144⅓ innings. Some of his numbers — walks and hits per inning, adjusted ERA — rivaled those of Pablo López and Sonny Gray.

I am not worried about Ober. He's poised to raise his game this season.

What I am worried about are some of the other spots in the Twins rotation.

The team chose not to re-sign Gray, who was the runner-up in American League Cy Young voting, or Kenta Maeda, who was a serviceable back-end rotation piece. While the Twins might have options to match Maeda's 4.23 ERA last season, they have not brought in an adequate replacement for Gray.

After getting out of the first round of the 2023 postseason for the first time since 2002, the Twins did not do enough this offseason to keep this rotation a strength.

The rotation was the foundation of the Twins' success last season, posting a 3.54 ERA at the All-Star break, its lowest since 1972. That's back when Jim Kaat was pitching. (Fun fact: Both Kaat and Gray were born on Nov. 7).

Here's another number for you: 139. That's how many starts the five-man front of López, Gray, Ober, Maeda and Joe Ryan made last season. That's 85.8% of the season. Only once in the last 10 full seasons have the Twins' top five made more starts than that (the 2019 Bomba Squad rotation).

That tells us two things. One, the 2023 rotation was largely consistent. Two, the rotation was largely healthy. This group has set the bar high for 2024.

"We lost guys like Sonny Gray and Kenta," Ober said. "We have so many arms to fill into those positions."

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They do have arms. No one is asking them to replicate what Gray did, although it would be nice. The Twins entered the postseason comfortable in knowing that Gray and Lopez were one of the best one-punches in the league. We don't know if Ober, Ryan, Louie Varland, a healthy Chris Paddack or someone else will emerge to form that kind of partnership with López.

We also can't expect the rotation to be as healthy as it was last season. Maeda battled a tricep injury and Ryan suffered a groin strain in June. That was mostly it. Injuries can be volatile from season to season. Let's examine the Twins' options in case the trainers have to be more involved this season.

They received righthander Anthony DeSclafani as part of a package for Jorge Polanco and were expecting him to be at the back end of their rotation. DeSclafani missed the final two months of last season with a sore flexor tendon. He hasn't pitched this spring because of soreness in the same area. He's missed two turns through the rotation, putting his availability for Opening Day in question. So the depth could be tested sooner rather than later.

After Varland, there are minor leaguers Simeon Woods Richardson, Matt Canterino, Brent Headrick, Randy Dobnak and David Festa. They could use a veteran option. The Twins watched Jake Odorizzi work out twice before camp opened but opted against a reunion. Lefthander Dallas Keuchel, who simmered with the Saints for a while before being called up late in the season, remains available as well.

Ober can solve some of this by progressing with his career, and I like his chances. He throws strikes, doesn't walk many batters and stays mentally tough if someone takes him deep. He's allowed 46 homers in his career, 30 of them solo shots.

Will his ascent be enough to make up for Gray's departure?

I have a feeling that the Twins will have to address the rotation before the trade deadline.