TAMPA, Fla. - CC Sabathia answered quickly.

Does the former AL Cy Young Award winner, World Series champion and unquestioned staff ace of three different organizations have something to prove this season?

"Of course I do,'' Sabathia said Saturday. "Not being able to play last year and performing horribly in 2013, I have a lot to prove. [I need] to come back out and be healthy and try to help this staff and help this team get back to the playoffs.''

The last two years have been the worst of Sabathia's pro career, and frankly, there hasn't been much to indicate things will get better.

The 34-year-old's fastball velocity took a drastic dip in 2013, and his struggle while adjusting to that situation contributed to his career-worst 14-13 record and 4.78 ERA.

And then it got worse.

Sabathia felt healthy in spring training last year and pitched well at times during the Grapefruit League season, but he did not get off to a strong start in the regular season. He was 3-4 with a 5.28 ERA through eight starts when the swelling in his right knee became too much, and his season ended after a May visit to Dr. James Andrews revealed a degenerative cartilage condition in the knee. He had arthroscopic debridement surgery in July.

By all accounts, the knee is healthy as he enters 2015 spring training. But the surgery didn't change two disconcerting facts: the degenerative condition -- "it's a bum knee,'' Sabathia said with a shrug -- and the fact that before the knee trouble cropped up, he wasn't pitching very well.

In the hopes of at least pumping up the velocity a little bit, Sabathia took the unusual step of actually getting heavier this offseason, reporting at 305 pounds compared to the 275 pounds he weighed when he reported to camp last year.

"I think last year I came in a little too light,'' Sabathia said after throwing a 25-pitch bullpen session. "I lost a bunch of weight drastically pretty quickly, I was kind of off-balance, I didn't really know how my body was working, so just talking to Dr. [Christopher] Ahmad and the trainers and stuff, felt like this is a good weight.''

He said that when he threw at home during the offseason and now in Tampa, he's noticed a difference.

"I feel a little stronger,'' he said. "Definitely my legs under me, feeling a lot stronger, and being able to push off the mound.''

Still, at this time of year, most everyone feels strong and just about everyone declares they are in the "best shape'' they've ever been.

Publicly, the Yankees aren't putting much pressure on Sabathia. Privately, they've set the expectation bar rather low, having no idea what to expect.

That feeling to some degree came out Saturday when Joe Girardi was asked about Sabathia's knee looking 100 percent during his bullpen session. "He did today,'' Girardi said. "I didn't see him favor it, I didn't see him stop or ask to not do any of his work. But as I've said all along, I think you have to get into it and the rigors of throwing 100 pitches and throwing every fifth day.''

Masahiro Tanaka clearly has assumed the role of staff ace, and if his spring training mirrors the performance he put together when healthy in 2014, Michael Pineda likely is the No. 2. Sabathia could slot in at No. 3, but his performance will dictate that.

"I don't think as an athlete you should lower your expectations,'' Sabathia said. But the reality of his situation seemed to stop him from expressing outright confidence in a turnaround. "I think you just go out and see what I've got, obviously,'' he said.

The seeds of doubt, without question, linger.

In addressing a question regarding his 2013 season, Sabathia didn't sound altogether certain that those numbers are behind him. "We'll see,'' he said. "Maybe that's what I am.''