When the Red Sox signed Garrett Whitlock to a long-term extension in the spring of 2022, they did so believing he could blossom into a mainstay of the starting rotation for years to come.

He still could, but it hasn’t happened as quickly as anybody would have preferred.

Over the past two years Whitlock’s progress has been hampered by a series of injuries. First there was the hip issue that derailed his 2022 season and necessitated major offseason surgery. Then last season he went on the injured list three separate times, first to complete his recovery from surgery but then due to two separate issues with his right elbow.

Those setbacks and the inconsistency they helped cause contributed to Boston’s fall to last place in each season, and Whitlock isn’t shy about admitting he hasn’t delivered on his end of the bargain.

“I’ll be the first one to say I think I was the worst guy on the team last year, so I think I need to pick it up a lot,” Whitlock said recently at Winter Weekend. “I think (Alex Cora) would tell you that, I think anyone that saw me last year would tell you that, so I’ve put a lot on myself to try and really step it up.”

Now Whitlock is determined to become the workhorse the Red Sox are counting on him to be.

Finally back to full health, Whitlock has hit the gym hard this offseason in hopes of building up enough strength to handle a full season’s workload. How that work translates on the field remains to be seen, but superficially the results have been impressive, as Whitlock turned heads all over Springfield with his notably improved physique.

“This is the first offseason I’ve been healthy in a while so I took advantage of it,” Whitlock said. “I took one week off at the end of the season and went straight back in and got to work in the gym. I wanted to do that to build strength and build up the right way.”

Whitlock’s current physical state stands in sharp contrast to last winter, or even compared to the majority of his tenure with the Red Sox. Acquired in the Rule 5 Draft from the New York Yankees ahead of the 2021 season, Whitlock was recovering from Tommy John surgery and spent the year in the bullpen while working his way back to full health.

His rookie season couldn’t have gone better, as he posted a 1.96 ERA over 73.1 innings and eventually emerged as the club’s closer down the stretch, but his transition to the starting rotation has been rocky. In 2022 he posted a 3.45 ERA over 78.1 innings while battling through the painful hip injury, which made it difficult for him to walk, much less pitch.

After undergoing surgery to correct the issue Whitlock spent all of last offseason rehabbing, and then once he got on the mound the elbow trouble popped up. He ultimately only made 10 starts, moving back to the bullpen in the second half to avoid any more issues and finishing with a career-worst 5.15 ERA in 71.2 innings.

Now that both his Tommy John and hip recoveries are both in the rearview mirror, Whitlock said he’s excited by the prospect of playing through a season with no restriction.

“They’re not playing with kid gloves any more, now it’s ‘go,’ Whitlock said. “I love that aspect and I’m eager to take that on.”

Whitlock isn’t going to have anything handed to him. As of now Boston’s rotation projects as Brayan Bello, Lucas Giolito, Nick Pivetta and Kutter Crawford, with Whitlock, Tanner Houck and Josh Winckowski expected to compete for the final spot.

Regardless of their ultimate role, Cora said Whitlock and others will have to be better for the Red Sox to have any chance of battling their way out of the AL East’s basement.

“At the end of the day, the Whitlocks, the Crawfords, the Houcks, the Bellos, they have to take a step forward,” Cora said at Winter Weekend. “Regardless of it you sign the best pitcher in the world, they need to take a step forward.”

You could argue nobody is more important in that respect than Whitlock, and if his struggles have been among the biggest reasons for Boston’s recent failure, his success could be the key to unlocking everything. Whitlock has already proven he can be dominant at the big league level, and if he can maintain that level of performance while also taking the mound every fifth day, it could completely transform the rotation’s outlook in both the short and long term.

“If you’re healthy and you can post 30-32 times, that kind of stuff, and be consistent throughout that’s all anyone can ask for,” Whitlock said. “So that’s my goal, consistency and health this year.”