The 27-year-old will begin a rehab program later this week at the Mariners' Spring Training complex in Peoria, Ariz., and when the right hip becomes strong enough, he'll have surgery on the left.
"The first couple of days after surgery were pretty tough," he said, "but I'm really encouraged by how well I feel. I am 100 percent positive that I'll be ready to report to camp on time and compete for a [starting] job.
"I am really looking forward to stepping on the field feeling confident that I am physically able to do my best on the field."
Much to his surprise, the catcher with whom he shared the position last season won't be there.
Kenji Johjima informed the team last weekend that he is opting out of the remaining two years of the three-year contract extension he signed in 2008 -- forfeiting $16 million -- and would finish his playing career in Japan.
The news caught Johnson by surprise.
"We were basically locker-mates, and we talked a lot," he said. "He never said anything to me about going back to Japan. I thought he was here for the long haul."
Club officials tried to arrange a conference call with Johjima on Tuesday, but he insisted on speaking only to Japanese media.
Johnson understands why Johjima would go home.
"We never really talked about his family, but I could see how happy he was when his boys [Yuta and Keita] were here. I get to see my 15-month-old son way more than Kenji got to see his kids."
General manager Jack Zduriencik said on Monday that he will look into adding a catcher before camp opens.
"That's a decision that will be made way above me," Johnson said of bringing in another catcher. "But whatever happens, everyone has to go out and prove that they can be the everyday guy."
At the moment, Johnson and rookie Adam Moore are first and second on the team's depth chart, though not necessarily in that order. Johnson's health could be an issue, and Moore has just six Major League games under his belt.
Johnson became ace right-hander Felix Hernandez's personal catcher early in the season, and the American League Cy Young Award candidate posted a 15-2 record with Johnson catching his pitches. Overall, the Mariners had a 46-29 record when Johnson was the starting catcher.
Though he refuses to use his injuries as an excuse, Johnson's offensive output -- .213 batting average, two home runs and 27 RBIs -- probably was affected by the hip and wrist issues he played through.
"I take responsibility for everything I did, or didn't do," he said, "but when you are injured and trying to play through pain, it can change the way you perform. After talking to a lot of guys who had similar things with their hips, it definitely hurt their hitting.
"The fact that both of my hips had abnormal bone growth, I just couldn't use the lower half of my body the way I should. There was some pretty bad impingement in there, and getting it fixed could make a big difference."