Chris Young could be out of the Mariners rotation. Rookie Taijuan Walker could be in.

That is the result the last two appearances from both pitchers. Young was mashed for five runs in 2/3 of an inning Monday in Oakland and has yielded eight runs in his last 4 1/3 innings. The fear is that he could be hitting a wall at 151 innings pitched this season.

"He's in uncharted territory," Lloyd McClendon told the Tacoma News Tribune. "I've got to watch him. I've got to evaluate him. I've got to make a decision."

McClendon indicated that Walker would replace Young in the rotation. Walker gave up just one run in six innings against Oakland in relief of Young.

"Obviously, he pitched extremely well," McClendon said. "I think it showed you what he's capable of. We've just got to get him to the point where he can be consistent every time out with that."