While most Mariners pitchers have already thrown three bullpen sessions and now a live batting practice outing, Hernandez still has to throw his third bullpen and then will have one live BP outing and a simulated game on one of the practice fields before he makes his Cactus League debut in early March.
"He won't be in the first games, same as he's done every year," Waits said. "He gets his stuff going on a backfield, then he's ready. He threw 22 [Cactus League] innings last year and 17 the year before. So somewhere between 20-25 innings is what we'll shoot for."
Waits said he has no concern over Hernandez getting ready in time by Opening Day.
"I don't because he's in great shape this year," said Waits. "He threw plenty enough before he came. And his first bullpen, he seemed ahead to me from his first bullpen last year."
Walker, 21, is a slightly different situation. The youngster had a sore arm upon arrival after throwing some hard sessions getting ready for camp. So he was held back initially and is just now gearing up.
Walker had a strong second bullpen session Thursday, but will still need several more bullpens before he graduates to live batting practice. Waits said Walker is completely healthy now, just slightly behind the other pitchers due to his late start.
"There are no issues at all," said Waits. "Today was an important day, the day after he threw his second bullpen, and he said he felt great. Hopefully he doesn't have any setbacks. We've got enough time to get him ready, but he's a little behind Felix."
Walker threw 35 pitches in Thursday's bullpen session, up from the 25 fastballs he fired in his first mound appearance Monday.
"I was pleased," said Waits. "He threw a few curveballs, but mostly fastballs and changeups. We need to do that again. There's no hurry to get to the off-speed pitches. The idea is to get the arm strength built up. When you've got the arm strength, you can throw anything."
Greg Johns is a reporter for MLB.com. Follow him on Twitter @GregJohnsMLB as well as his Mariners Musings blog. This story was not subject to the approval of Major League Baseball or its clubs.