After hitting .295 in his first three months with Seattle, Ackley batted .219 in September. Pineda made the All-Star team with a powerful first half -- then didn't win a game after July 30, as his numbers dipped in the final two months.
Rookie outfielder Trayvon Robinson acknowledged he was ready for a break in the final days of the season. The youngster impressed early with a sensational catch and home run in his first two games for the Mariners in August, after being acquired from the Dodgers. But after hitting .261 in August, he batted .162 in September and struggled defensively at times, as well.
"I want to lay low right now, give my mind a rest," Robinson said before heading home to Los Angeles. "I might go to the second half of winter ball or something, but right now, I just want to chill.
"This will be my first time off in a long time, and I think I need it -- just to get my mind off the game a little and then be ready to go when the bell rings again. I've had a lot of transition this year. I've been through a lot. I need to give my body and mind a chance to catch up."
Robinson had some humbling moments during his first exposure to the Major Leagues. That's part of the process for the Mariners, as they pushed 18 rookies to the fore this past season -- some before they were really ready.
"It's been interesting," said Robinson, who played a combined 147 games, with 520 at-bats, between Triple-A and the Majors this season. "I learned a lot, and I just want to learn more and more. I tried to take at least one thing home each day, whether it was a bad at-bat or bad game or good game, just take one thing home and learn from it.
"The truth hurts. Reality hurts. But you have to fight through it. It's just like life. You've got to go through it. I've been through a lot in baseball. Striking out four times hurts. But I'm pretty sure it's not going to put me six-feet under. It's not going to kill me. When I have those games, I just have to turn the page and learn from it."
Like some of his other young teammates, Robinson will turn the next page in the spring -- with a refreshed mind and body that will now understand better the rigors of preparing for a 162-game season.
Carp showed the way last winter, with an offseason regimen and diet that helped him lose 20 pounds and increased his quickness and bat speed -- a major reason for his breakout year.
So even those who aren't playing winter ball understand the work to be done.
"We've got a lot of young guys who had never gone through a full Major League season, like myself," said first baseman Justin Smoak. "Now, we know what the grind is, and physically what you've got to do to be ready, body-wise.
"There's going to be a lot of hard work going on this offseason to get better, and get our bodies in shape and ready for a long season. My plan is to get after it. That's my No. 1 goal, to do what it takes to get stronger and flexible and quicker."
Five players who spent time with the Mariners this season will be playing winter ball: outfielders Michael Saunders and Carlos Peguero, third baseman Alex Liddi, infielder Luis Rodriguez and reliever Cesar Jimenez.
For Saunders, the decision was simple. He hit just .149 in 58 games with the Mariners, and he knows he needs to work on the adjustments that didn't carry over from Triple-A to the Majors.
"It's a chance for me to stay on my approach," Saunders said. "I took a lot of time off this season, due to problems in my personal life. So I just want to get more at-bats."
Here is the full list of Mariners playing this offseason:
Venezuelan Winter League
Cardenales de Lara: RHP Vicente Campos, 2B/3B Edilio Colina, RHP Jarrett Grube, RHP Moises Hernandez, LHP Cesar Jimenez, LHP Jose Jimenez, 1B Luis Jimenez, 3B Liddi, OF Johan Limonta, 3B Mario Martinez, RHP Yoervis Medina, RHP Scott Patterson, RHP Stephen Pryor, LHP Mauricio Robles, OF Saunders, 3B Nate Tenbrink
Tiburones de La Guaira: INF Luis Rodriguez
Leones de Caracas: C Jesus Sucre
Magallanes: OF Yohermyn Chavez, 3B Francisco Martinez
Dominican Winter League
Estrellas Orientales: OF Leury Bonilla
Aguilas Cibaenas: LHP Edward Paredes
Club Atletico Licey: OF Peguero, SS Carlos Triunfel
Puerto Rican Winter League
Carolina: OF Daniel Carroll
Australian Baseball League
Adelaide Bite: OF Denny Almonte, C Steven Baron, OF James Jones, RHP Jandy Sena
Arizona Fall League
Peoria Javelinas: OF Chih-Hsien Chiang, SS Nick Franklin, RHP Steven Hensley, LHP Danny Hultzen, C Adam Moore, LHP Brian Moran, RHP Forrest Snow