SEATTLE -- Right-handed reliever Shawn Kelley, who had partial Tommy John surgery on his elbow on Sept. 1, rejoined the Mariners Thursday to continue his rehabilitation and said he's on schedule to be ready to pitch when his 60-day disabled list stint ends June 1.

Kelley, 26, has been throwing at the team's Spring Training complex in Peoria, Ariz., in recent weeks, but has progressed to the point where he'll work out and travel with the Mariners now until he's ready for some Minor League rehab outings.

"I've been throwing successful bullpens, all fastballs, and I feel good," Kelley said after exchanging greetings with numerous teammates upon his arrival in the Safeco Field clubhouse before Thursday's game against Oakland. "I feel strong. But I'm just taking it day by day and not getting too excited."

Kelley had full Tommy John surgery when he was 18, but this time the ligament didn't completely detach and his recovery has been far quicker than normal.

He was 3-1 with a 3.96 ERA in 22 outings last season before going on the disabled list on June 25. He's appeared in 63 games over the past two seasons in Seattle.

"It definitely feels like there is a light now at the end of the tunnel, being out of Arizona, because that was just like an extension of spring without all my friends," he said. "I did what I needed to do, it was warm there, but it's definitely a good feeling being back with the team today."

As for a return when his DL stint potentially ends in 5 1/2 weeks?

"That's the plan," Kelley said. "What they do decision-wise is up to them, but based on the amount of time I have for bullpens and a rehab assignment, there's no reason right now, the way things are going, that by June 1 I wouldn't be fully game ready."

The Mariners will have to clear a spot on the 40-man roster to make room for Kelley whenever he is brought off the 60-day DL.

Third baseman Matt Mangini, who has been on the 15-day disabled list with a quadriceps injury suffered in Spring Training, was activated Thursday and optioned to Triple-A Tacoma, where he immediately was placed in the starting lineup for the Rainiers.

Bradley out of Mariners' lineup with illness

SEATTLE -- Left fielder Milton Bradley was scratched from the Mariners' lineup several hours before Thursday's game against Oakland and replaced by rookie Carlos Peguero, who will make his second straight start for Seattle.

Manager Eric Wedge said Bradley wasn't feeling well, but he hoped the veteran would still be available for late-inning duty if needed.

Peguero, 24, was called up from Triple-A Tacoma on Tuesday when first baseman Justin Smoak went on the bereavement list due to the death of his father in South Carolina.

Peguero made his Major League debut Tuesday night as a ninth-inning defensive replacement in a 13-3 win, then went 0-for-4 with three strikeouts while starting in left field in Wednesday's 3-2 loss. Bradley was given Wednesday off as a regular rest day, but came to the park not feeling well Thursday.

Wedge wasn't going to judge too much from Peguero's first start, but said he liked the aggressive approach of the 6-foot-5, 247-pounder, and has the big lefty batting seventh again against A's right-hander Brandon McCarthy.

"I feel like any time it's your first day, it's a special day," Wedge said. "He had some opportunities and he went out there, he was aggressive, swung the bat. We were in the ballgame and had our opportunities and he was part of that.

"I'll tell you this -- he's a big, strong, aggressive guy, aggressive hitter, with some athleticism, which we saw this spring in the outfield at times. He's out there ready to go. It's nice to see."

Kennedy forcing his way into Mariners' lineup

SEATTLE -- When the Mariners signed infielder Adam Kennedy as a non-roster invitee over the offseason, they were looking for exactly the kind of veteran presence and versatility that the 35-year-old has provided through the first three weeks of the season.

Kennedy started at first base on Thursday, his 10th start in 20 games, while his .314 batting average tops the team in the early going.

Kennedy has started six games at second base, three at first and one at designated hitter, while also coming off the bench for three pinch-hit opportunities.

Manager Eric Wedge has even convinced Kennedy to serve as the emergency No. 3 catcher if needed, behind Miguel Olivo and Chris Gimenez.

The last time Kennedy caught in a game?

"Maybe Little League or something," Kennedy said. "Hopefully it doesn't come down to that, but whatever. I don't really care at this point. I just want to play."

Earlier in the year, Kennedy filled in quite a bit at second base when Jack Wilson got benched. This week, he's getting increased time at first base with Justin Smoak on the bereavement list following the death of his father. He's playing first against right-handed pitchers, while Gimenez works there against lefties.

Gimenez went 2-for-3 with a big two-run single in Tuesday's 13-3 win over the Tigers, while Kennedy was 2-for-4 with a solo home run in Wednesday's 3-2 loss.

"Gimmy had a good game [Tuesday]," Kennedy said. "Hopefully we can hold it down for a couple days until [Smoak] gets back."