Mariners pitchers begin to find out who's No. 2

Because the Mariners are playing their first two regular-season games against Oakland in Japan, they will become the first major league franchise to hit the field for spring training. Pitchers and catchers report to the club’s Peoria, AZ., complex Saturday, with position players arriving Friday.

The Mariners will hold daily workouts until March 2, when they play their first spring training game, away against the Athletics, whom they will contest in the major league opener March 28 in Tokyo. Following a second game at the Tokyo Dome the next day, the Mariners will return to Arizona to complete spring training.

Seattle’s 2012 season opener is April 6 at Oakland, and its home opener is April 13, also against the Athletics.

The most significant rotation issue is the pursuit of an adequate replacement for Michael Pineda, whom the Mariners swapped to the New York Yankees, along with RHP Jose Campos, for C Jesus Montero and RHP Hector Noesi Jan. 23. In his rookie season, Pineda went 9-10, 3.74 and made the All-Star team.

As spring training opens, Seattle’s projected rotation includes, in order, RHP Felix Hernandez, LHP Jason Vargas, RHP Hisashi Iwakuma, RHP Kevin Millwood and RHP Blake Beavan.

Hernandez, Vargas and Beaven are holdovers from last year’s staff. Only one of the five projected starters, Millwood, produced a winning record in 2011, and Millwood only did so in limited appearances.

Seattle’s ace, Hernandez, the 2010 Cy Young winner, went 14-14 with a 3.47 ERA last season in 33 starts. His ERA was more than a run higher than the 2.27 he posted in his Cy Young season. His innings were down 233.2 to 249.2. But Hernandez pitched well enough to make the American League All-Star team.

Vargas began the 2011 season as the No. 2 starter in Seattle’s rotation, but was dropped to No. 3 before the season was two weeks old in the wake of Pineda’s startling emergence. Vargas went 10-13, 4.25 ERA in 32 starts. He threw four complete games and three shutouts, the first three of his six-year major league career.

A ground-ball pitcher who mainly uses a splitter as his out pitch, Iwakuma throws a fastball in the 87-94 mph range. Sidelined with shoulder woes last season, Iwakuma went 109-67 with a low walk rate during his career in the Japan. The Mariners signed Iwakuma to a one-year deal for $1.5 million, with another $3.5 million in incentives.

Millwood, a 15-year major league veteran (mostly with Atlanta and Texas), signed a minor league contract with the Mariners after pitching in nine games in 2011, all with Colorado. He went 4-3 with a 3.98 ERA. He hasn’t had a winning major league season since 2006 when he went 16-12 with Texas, and two years ago lost 16 games with Baltimore.

Beavan, acquired from Texas in mid-2010 in the Cliff Lee trade, went 5-6 with a 4.27 ERA in 15 2011 starts. The 22-year-old also made 16 starts for the AAA Tacoma Rainiers, going 5-3.

As spring training commences, Brandon League, who had 37 saves (2.79 ERA) last year when he made the All-Star team, is Seattle’s closer. The Mariners have penciled in Tom Wilhelmsen (3.31 ERA) as the right-handed set up man, and George Sherrill (a Mariner from 2004-07) as the left-handed set-up man.

Wilhelmsen, who split 2011 between AA Jackson and Seattle, saw action in 25 games, going 2-0, 3.31. Sherrill pitched in 51 games for Atlanta, going 3-1, 3.00.

Three newcomers could figure prominently in the plans.

Acquired in the Pineda trade, the 25-year-old Noesi will be given a chance to make the rotation during spring training. As a rookie in 2o11, he pitched mostly in relief for the Yankees, but did start twice.

LHP reliever Hong-Chih Kuo, an All-Star in 2010 with the Dodgers, pitched in just 40 games (27 innings) in 2011, when he experienced control issues. If he can return to his 2008-10 form, the Mariners have made a significant addition to their bullpen. He’ll make $500,000 but that will increase to $1 million if he makes the 25-man roster.

RHP reliever Shawn Camp, 36, might fill the same kind of role that Jamey Wright held last season, as a veteran bullpen workhorse. Camp appeared in 67 games for the Blue Jays in 2011, going 6-3 with a 4.21 ERA. The Mariners signed him to a one-year deal worth $750,000 earlier this week.