PEORIA, Ariz. -- The risk of taking two steps backwards after taking several steps forward has altered the Mariners' immediate plans for left-hander Erik Bedard.

One day before he was going to throw off a mound for the first time since having the labrum in his left shoulder repaired, the Mariners on Monday changed course and will stick with a conservative approach.

Manager Don Wakamatsu said the decision to scratch the bullpen session was related to one of the recent long-toss sessions.

"He had a little bit of stiffness, more like a tired arm the other day," Wakamatsu said. "He's been throwing quite a bit in his long-toss program. He felt it two days ago, so we're going to be cautious about it. But I think we're in good shape."

The usual recovery period for labrum surgery is 10 to 12 months, and it has been slightly more than seven months since Bedard had the labrum in his left shoulder repaired.

"He is so far ahead of what he's supposed to be," head athletic trainer Rick Griffin said. "What we are trying to do is make sure there are no setbacks."

His recovery progressed so well after the Aug. 14 surgery that the Mariners re-signed him to an incentive-laden one-year contract with an option for 2011 on Feb. 6, hoping he would be able to rejoin the starting rotation for the second half of the season -- if not a little sooner.

But the Mariners are taking the better-safe-than-sorry approach.

"He's not ready, in our esteemed opinion," Griffin said. "We just don't feel like we want to push him. We want him to progress on a steady line, and we have been doing that so far. We just want to maintain that."

So instead of taking the big step from flat ground to a pitching mound, Bedard will stick with his current rehab program for the time being -- throwing hard from 120 feet for 15 minutes and flat-ground bullpen work.

At some point, he will graduate to the mound.

"We don't know exactly when that will be," Griffin said.

"There is a lot more force throwing on a downward plane," the longtime trainer explained. "Your mechanics change, your arm angle changes and it puts a lot more stress on your shoulder.

"I remember Nolan Ryan telling Randy Johnson that as he got older, he didn't throw some of his bullpen sessions off a mound. A lot of times he would just do flat-ground work [between starts] because of the pressures throwing off a mound. Randy started doing that."

The difference can be so dramatic, in fact, that one misstep during the recovery process could lead to a major setback.

"A lot of times when you are rehabbing a guy's shoulder, they progress and never have a problem," Griffin said. "Everything is going along smoothly, and the first time they throw off the mound there is a setback because there is such a big change. That's what we are trying to avoid. We want to be in a position that we continue to progress forward."

Bedard has made 30 starts in his two seasons with Seattle, posting an 11-7 record, 3.24 ERA and 162 strikeouts in 164 innings -- the sort of numbers the Mariners would like to see from him again this season.

Meanwhile, on the Mariners' injury front:

Griffin said left-hander Cliff Lee will play "a normal game of catch" on Tuesday, testing the right abdominal strain he sustained on March 15 in his second Cactus League start.

"We have to gauge where he's at, see how he feels and go from there," Griffin added.

Right-hander Doug Fister, who took a line drive off his right forearm on Friday, also will play catch on Tuesday.

"It is still a little bit tender," Fister said, "but today is Day 3 and it's a lot better. There is a lot more mobility and less tightness."

The arm is still swollen, but nowhere near what it was the day after being plunked.

He said so much progress has been made in the past three days that he expects to be ready to go when the regular season opens two weeks from Monday.

Infielder Jack Hannahan, sidelined since March 4 with a right groin injury, fielded ground balls on Monday and it didn't go particularly well.

"He picked up some grounders and is a little stiff, so we're going to check him out," Wakamatsu said. "It's been kind of a lingering thing, so we're going to check him out and see if there's not something more serious in there. He just didn't feel like he was 100 percent, and we felt he would be more advanced than that."

As it is, Wakamatsu said there might not be enough time remaining for Hannahan to be ready for the regular season.

Left-hander Garrett Olson (injured finger) played catch on Monday and all systems are go for his return to action.