PEORIA, Ariz. — All the talk surrounding Franklin Gutierrez this spring had been about the 15 extra pounds of muscle he packed on to his healthier body.

But a torn muscle in his chest is significant enough that he'll begin the season on the disabled list and likely will not play for the Mariners before the month of May. The team announced Wednesday that Gutierrez has a partially torn pectoral muscle and won't be able to resume normal baseball activity for at least four weeks.

That means he'll essentially be starting spring training over again as the Mariners are playing regular-season games.

The rehabilitation process normally requires any ballplayer at least a couple of weeks to get properly conditioned and then several more weeks of minor-league games to be in major-league playing shape.

"At this point, we don't know," Mariners general manager Jack Zduriencik said of how much Gutierrez could be ready to do in four weeks. "Everybody responds to things differently. We don't know what he'll be able to do, and at this point, we'll probably just ease him into things gradually."

Gutierrez injured his pectoral muscle while making routine throws from the outfield to third base during a drill Tuesday morning.

He had a magnetic-resonance-imaging scan done later in the day, then flew back to Seattle to get another MRI and to discuss the results with team medical director Dr. Edward Khalfayan.

A decision was made to treat the torn muscle without surgery, so Gutierrez will be in a sling for 5 to 7 days and then he'll rest at least until after the team opens the regular season in Japan. Once his four-week rest is over, he'll be re-evaluated on a week-to-week basis as the team breaks him back in cautiously.

The latest setback in the injury-and-illness-plagued career of the team's athletically-gifted center fielder has left the door wide open for someone to grab the position full time in his absence. Zduriencik mentioned Michael Saunders, Casper Wells and Chone Figgins as the leading candidates.

Figgins started an intrasquad game in center field Wednesday. He hasn't played center since 2006 with the Angels.

"Figgins played 244 games in the majors in center field, don't forget," Zduriencik said. "We just haven't seen him do it here. And that's what we'll have to evaluate."

But of the multiple positions Figgins has played throughout the course of his career, his best has been third base. The team planned to work him into some games in the outfield, but going back to center full-time wouldn't be the first choice.

Of the three players, Saunders would be the most natural fit in center. Saunders also handled the bulk of center-field duties for the team last year when Gutierrez was slowed until mid-May by irritable bowel syndrome.

The only question with Saunders is whether he'll hit. His defense was solid last year but his average floundered below .200. He revamped his swing this offseason. Saunders has been hitting the ball with authority in intrasquad games, belting a three-run homer off Shawn Kelley on Tuesday.

"I'm very happy so far," Saunders said. "People will say, 'Oh, it's just intrasquad.' But it's still baseball. It's still a competitive game environment."

Wells has gotten off to a slower start with his bat. He hit a single on Wednesday, but also struck out twice.

The Mariners know Wells can play the outfield corners well but aren't sure about him as an everyday center fielder. One thing he does have that Saunders lacks is a right-handed bat, something the team loses with Gutierrez sidelined.

In any event, if Saunders and Wells hit this spring, there's a good chance they'll both make the squad — one as a center fielder, the other a fourth outfielder.

"We're going to watch and see how it all plays out," Zduriencik said. "We'll see what these guys show us."

Geoff Baker: 206-464-8286 or gbaker@seattletimes.com.

On Twitter @gbakermariners