Problem is, it's hard to. Because, for most of the last 16 starts he made in an Angels uniform, Wilson simply wasn't himself. He gave up five or more runs five times, couldn't get through six full innings on eight occasions, and though he was better toward the end, Wilson finished the second half with a 5.54 ERA, the Angels winning only half of the games he started.
Then, after it was all said and done, Wilson finally revealed that he wasn't healthy. His elbow was barking, just like it did five years ago, and the 32-year-old left-hander was once again forced to have bone spurs removed from his pitching elbow in the offseason. The procedure was minor -- one that hardly even interrupted his throwing program -- but Wilson believes it was essentially the reason he struggled down the stretch.
Don't mistake that for an excuse, though. Wilson isn't offering any.
"It's the Major Leagues," he said. "This isn't the Hallmark greeting card aisle. No one feels bad for us when we lose.
"You win at all costs, and you go compete until you're unable to compete anymore. I was at a point where I knew I wasn't 100 percent, but a lot of us in the locker room weren't 100 percent, so I was like, 'Let me see if there's a way I could pitch around it.'"
What Wilson went through wasn't anything muscular, so temporarily shutting it down wasn't going to make it any better. He learned that lesson during his reliever days in 2008, when he took some time off, watched his elbow get worse and ultimately relented to removing bone spurs.
So the only solution in 2012 was the procedure.
In the meantime, the only option Wilson saw was to shut up and keep pitching -- regardless of the maddening struggles caused by something nobody outside the Angels knew he was dealing with.
"My job is to go out there and win games, and if I don't win games, I'm the one that's failing," said Wilson, signed to a five-year, $77.5 million deal in December 2011. "There's no asterisk on the back of my baseball card that says, 'Didn't feel good from July to August.' Nobody cares. It doesn't matter."
What does matter, with regard to an Angels team that comes into 2013 with question marks in its rotation, is whether that tune-up could get Wilson back to being the successful pitcher he was for 2 1/2 years, through back-to-back World Series runs with the Rangers and a monster first half in Anaheim.
If it does, suddenly the Angels have one of the best top-of-the-rotation duos in the American League, easing some of the pressure on the new trio of Jason Vargas, Tommy Hanson and Joe Blanton.
"I think we'll see much more of that first-half guy from C.J. than the guy who was a little erratic in the second half," Angels manager Mike Scioscia said. "His command will be better; I think he'll definitely be able to put hitters away better. Some of the things that he did in the first half and what made him good, he had a tough time executing it in the second half. It became a challenge."
Post-surgery, Scioscia has seen Wilson get back his full range of motion while more effectively executing every pitch -- and Wilson throws a lot of pitches -- during bullpen sessions.
This spring, beginning with his debut against the Brewers on Saturday, Wilson will mostly look to keep getting used to pitching from the first-base side of the rubber. He initially did it to compensate for the elbow -- since it allowed him to be more on top of left-handed batters and away from righties while his sinker was off -- and liked it enough to stick with it.
In a vacuum, Wilson's 2012 season was a success. He reached double-digit wins (13), had an ERA under 4 (3.83) and topped 200 innings (202 1/3).
But it left a sour taste.
"Perspective-wise," Wilson said, "I think a lot of pitchers would take those results. Not me. I'm not happy with that."