Could the Mariners actually go into this season with two rookies in their starting rotation? Isn't that a recipe for disaster?
-- Phil P., Seattle, Wash.

Well, in 2012, the A's won the American League West title with four rookies playing prominent roles in their starting rotation, including a pair of 13-game winners in Tommy Milone and Jarrod Parker, then added another quality rookie starter last year with Dan Straily. So the question isn't necessarily experience, but production.

Have a question about the Mariners?
Greg JohnsE-mail your query to MLB.com Mariners beat reporter Greg Johns for possible inclusion in a future Inbox column. Letters may be edited for brevity, length and/or content.
First Name, Last Initial:

Hometown:

Email Address:

Question:

I expect Taijuan Walker to earn a starting job this spring. That's not exactly a bold prediction, given manager Lloyd McClendon is on record saying he'll be disappointed if Walker doesn't win a job in camp. James Paxton certainly has a shot as well, if he pitches as well as he did in September when he went 3-0 with a 1.50 ERA in four starts against some excellent competition.

Unless Seattle signs another starter in the coming days, those two rookies will compete with fellow youngsters Erasmo Ramirez, Brandon Maurer and Blake Beavan and veteran non-roster invitee Scott Baker for the final three starting spots behind Felix Hernandez and Hisashi Iwakuma.

Ramirez and Maurer are both 23, but neither is considered a rookie since both have pitched more than 50 innings in a Major League season. Beavan just turned 25, the same age as Paxton. Walker truly is the baby of the bunch at 21, which is why they'll be more careful with his innings than any of the others.

What Mariners player do you think might surprise us with a breakout year?
-- Sara B., Bremerton, Wash.

There are a couple young guys getting overlooked now that could easily emerge if they get the chance. People seem to be writing Nick Franklin off after the signing of Robinson Cano, but Franklin will compete at shortstop with Brad Miller and, at 22, learned a great deal from his experience last year. Franklin reminds me of a young Bret Boone, a brash kid who'll get better as he learns the game and himself.

Just like a year ago at this time, all the pre-camp pitching focus has been on Walker and Paxton. But don't forget about Maurer, who beat out both of those guys in camp last year and now returns at age 23 with a lot more knowledge and confidence.

I'm interested to see how Tom Wilhelmsen comes back after a difficult 2013 season, now with Fernando Rodney coming aboard. Wilhelmsen has nasty stuff, a live arm and added motivation. He should still play a big role in this year's bullpen. And in the outfield, Abraham Almonte is flying under the radar after displaying an intriguing speed and power combination late last season.

With the new rules allowing instant-replay challenges, how many minutes do you think will be added to each game?
-- David E., Tacoma, Wash.

Instant replay will be a work in progress initially, and the timing will be closely watched and debated. The actual challenges shouldn't take too long, as on-field umpires won't retreat into the tunnel to review calls, but instead will communicate directly via headsets with an umpire crew monitoring television replays of games in a New York City studio.

Each umpire crew will take regular rotations in the NY headquarters, so we're not talking about former or retired umps. These are guys used to making snap judgments on live plays, and I suspect they'll be pretty quick in making calls with the replay system.

What might slow games down is if managers and players frequently start stalling on the field in order to buy time to let their own video people view plays before deciding to challenge. If the pitcher and catcher start conversing or an infielder goes to talk to the pitcher every time a close play occurs, that could get tedious. So we'll see how umpires -- and managers -- handle the new system.

I saw recently that the Mariners have invited 65 players to Spring Training (40 roster players and 25 non-roster invitees). Is there a limit to how many players a team can invite to camp? If not, is it to a team's advantage to invite as many players as possible?
-- Bill C., Forks, Wash.

There is no limit, other than time and space constraints. Teams don't want too many players in camp, because that overcrowds clubhouses and makes it difficult to get everyone sufficient repetitions in on-field drills. And once Cactus League games begin, there's only so much playing time to go around. But I suspect the Mariners will add another non-roster veteran or two before camp opens.

With Dustin Ackley, Michael Saunders and Franklin Gutierrez all competing for outfield spots, who do you see playing center field?
-- Sean E., Boise, Idaho

Gutierrez played more right field last year in an effort to reduce the wear and tear on his body, and I expect that strategy to continue, at least initially, as keeping him healthy has been the biggest challenge for the last three years. But that depends also on how much Corey Hart and/or Logan Morrison can play right field, given their knee questions. If those two can play more right field, Guti could be back more in the center-field mix as a needed right-handed hitting option.

Ackley played a lot of center last year -- that was the position in which he felt most comfortable when he was thrown into the outfield mix midseason -- but I suspect he'll play a lot of left field as well as center in camp this year. No longer is there any need to work him at second base, since Robinson Cano holds that job. Saunders is pretty natural at all three positions, and in my book, the favorite to earn the center-field job if he plays well.