MESA, Ariz. - Cubs prospect Junior Lake will miss the rest of camp and the first part of the minor league season after an MRI revealed a stress fracture at the back of his top right rib, the club said Wednesday.

Lake, a shortstop making the conversion to third base, had been sidelined the last several days with what originally was believed to be a sore shoulder.

Lake was 7-for-23 this spring with a homer, triple and eight strikeouts.

Manager Dale Sveum hoped to see more of Lake, especially in the outfield, but saw enough to know how much development the raw, 23-year-old player needs.

"[He has] all the tools,'' Sveum said. "Swinging the bat, he's obviously got a lot to learn. He's a very premeditated swinger. He's not getting good pitches to hit. He's swinging at arm action a lot. And he's a guy with a lot of bat speed that doesn't have to be a premeditated swinger.

"It's a nice player to have, but there's still development there."