SEATTLE — Fact: Mariners third baseman Kyle Seager batted .238 with 13 homers over 638 at-bats in his first three seasons at Safeco Field.

Fact: Seager is batting .311 this season in 36 games at Safeco and already has nine homers in 119 at-bats.

Fact: Seager had 33 RBIs last season in 80 games at Safeco. This year, he already has 30. His on-base percentage at home is nearly 100 points higher than his career mark coming into the season.

Fact: There are a bunch more facts in this vein, but you get the idea.

Question (obvious): What’s going on?

“I’m not doing anything different,” insisted Seager, who contributed a two-run double to Tuesday’s 6-1 victory over the Padres. “It’s just one of those things. But I’m going to ride the wave.”

On reflection, he added: “The numbers weren’t really good (in the past), I guess, but it’s just one of those things. You get into a rhythm, and you start feeling good. It’s worked out that I’ve been in that rhythm at home.”

Any explanation for the power surge? The fences, after all, were shortened prior to last season.

“Not that I’m aware of,” Seager said, shaking his head. “It’s just one of those things, but I’ll take it. I’m not giving them back.”

Iwakuma slowed

Right-hander Hisashi Iwakuma skipped his regular between-starts bullpen workout Tuesday because of continuing problems with a stiff neck.

Iwakuma did play catch from flat ground and did his regular running regimen in the outfield. He remains listed as the Mariners’ starting pitcher for Friday’s series opener at Kansas City.

Manager Lloyd McClendon said “As I speak now, he will not miss a start.”

Iwakuma’s ailment surfaced prior to his start Sunday against Texas, but he pitched eight innings and limited the Rangers to one run and six hits in a 6-1 victory.

Montero at first

Jesus Montero started at first base for the first time in his big-league career — and McClendon’s pre-game comments suggested expectations were modest.

“We’ve got a left-hander going (Eric Stults for San Diego),” McClendon said, “and we need a first baseman. I’m not playing the left-handed first baseman (Logan Morrison).”

Asked why he had the necessary confidence to put Montero at first base, McClendon responded: “I never said I had confidence. I said I need a first baseman. He’s available, and that’s who we’re going to put out there.”

The hope was Montero could deliver with his bat…as happened in the second inning when his two-run homer erased a 1-0 deficit.

Montero, a former catcher, converted to first base last season at Triple-A Tacoma and played 64 minor-league games at his new position over the last two seasons.

Even so, he was surprised to see he was playing first base on Tuesday.

“The first thing I thought was…I got nervous,” Montero said. “But after that, I hit the homer and I felt better. I relaxed, and I got some confidence. I made a couple of plays in there.”

And defensively? He handled eight chances with no problems, including one grounder, before Morrison entered the game as a defensive replacement in the seventh inning.

Short hops

First baseman Justin Smoak, outfielder Michael Saunders and first baseman/outfielder Corey Hart are all expected to report Wednesday to Tacoma to continue their recovery from injuries. All three are expected to play by this weekend. Smoak is recovering from a strained left quadriceps muscle, Saunders from a sore right shoulder and Hart from a strained left hamstring…center fielder James Jones went 3-for-5 and is batting .349 (15-for-43) over his last 10 games…Kyle Seager had his third straight multi-RBI day when he blooped a two-run double in the seventh inning. He has 25 RBIs in his last 29 games….The Mariners’ starters have allowed one or no runs in each of the last five games.

Looking back

It was 12 years ago Wednesday — June 18, 2002 — that Ken Griffey Jr. played against the Mariners for the first time as an opponent. It was also the Mariners’ first game in history against Cincinnati — and they won 8-1.

Griffey had two singles and a walk in four plate appearances at old Cinergy Field (Riverfront Stadium) in Cincinnati.