GOODYEAR, Ariz. -- Scott Lewis said what everybody else was thinking.

"Wow."

What else could be said after the left-handed Lewis gave up 10 runs on 13 hits in just 3 2/3 innings against the Mariners on Tuesday at Goodyear Ballpark? Especially considering Lewis, awarded a rotation job a week ago, had given up five runs in three innings against the Angels in his previous start.

Well, Lewis did have plenty to say, as it turned out, and most of it involved the dry Arizona air and its effect on his grip.

"I've been struggling with some issues with the grip on the ball," Lewis said. "The ball's been slipping the last couple times out. I've been going to the rosin bag, trying to get a grip, and losing focus. My delivery's been off, and the pitches aren't doing what I want them to do right now."

That much was apparent as Lewis served up a two-run shot to Russell Branyan in the third and a grand slam to Ronny Cedeno and a solo shot to Branyan in the fourth. Branyan's homers landed somewhere between here and Albuquerque.

Lewis said he couldn't get a grip on his breaking ball, so he went to the fastball more than he'd like. And his fastball command was obviously off, especially on the grand slam.

"I was finally starting to get dialed in on the outside corner," Lewis said. "I'm sure [Cedeno] was looking for the fastball, and I caught a lot of the plate with that one."

That's now six home runs allowed by Lewis in his past 6 2/3 innings. He allowed four homers in 24 innings in the big leagues last September.

Lewis, who had a 3.52 ERA in 15 1/3 innings over his first five Cactus League appearances, had pitched well enough to earn the Tribe's fourth rotation spot, and that only serves to make these recent struggles all the more confounding. If lack of humidity is the culprit now, it certainly wasn't bothering him earlier in camp, and it's not a problem that's going to go away when the Indians play their April 10 home opener at Progressive Field -- a game Lewis has the honor of starting.

"Cold weather does the same thing," said Lewis, who now has an 8.59 ERA. "That's why I was trying to get it figured out before I took off, because I'm sure it's going to be chilly in Cleveland."

Lewis said he's healthy and his arm feels fine. He'll have one more tuneup in an extended Spring Training game at the Player Development Complex on Sunday, and he knows he has to figure it out soon. The Indians have rotation depth at Triple-A Columbus, in the form of young lefties David Huff, Jeremy Sowers and Aaron Laffey and veteran right-hander Kirk Saarloos, and they're not expected to be shy about using it.