I wouldn’t say the Seattle Mariners organization is the deepest system in the majors but it has some of the best upper-tier talent among the 30 baseball clubs. What’s even more impressive with the organization is that so many of those top prospects are pitchers and up-the-middle position players. Also, unlike a lot of the top systems in the game, the bulk of Seattle’s talent is at the double-A and triple-A level suggesting better days are ahead for the Mariners and their fans.

#1 Michael Zunino (C/DH)

Age PA H 2B HR BB SO SB AVG OBP SLG wOBA 21 276 81 18 15 28 53 2 .336 .413 .614 .461

It’s not often you can say this when a club chooses a player third overall in the amateur draft, but the Seattle Mariners may have gotten a steal with Zunino. The University of Florida alum made an immediate impression upon turning pro by hitting for power, average and showing a good understanding of the strike zone. After posting a 1.210 OPS in 29 Northwest League games, Zunino had a .974 OPS after a three-level promotion to the double-A Southern League. And if that wasn’t enough, he posted an .800 OPS in 19 Arizona Fall League games.

Although his hit tool may end up being underrated – a lot of evaluators project it as average – there probably aren’t many, if any, that would argue his right-handed power is a plus tool. Along with his intriguing bat, Zunino possesses all the intangibles that make up good a field leader. His defense projects to be average or a hair above, but he shows a promising game-calling skills and an average arm.

Zunino could not have had a better pro debut and it will be interesting to see where he starts off the 2013 season: double-A, triple-A or the majors. A strong spring could push the organization to start the year with him as the club’s starting catcher – especially since the American League West should be quite competitive and the club may need every win it can squeak out. However, with John Jaso and Jesus Montero (who could move to a full-time DH with Zunino’s promotion, or be flipped in a trade to fill a more glaring hole) are probably quite capable of holding down the fort until Zunino truly forces the Mariners’ hand.

#2 Taijuan Walker (P)

Age G GS IP H HR K/9 BB/9 ERA FIP 19 25 25 126.2 124 12 8.38 3.55 4.69 4.04

If Zunino wasn’t a steal, Walker certainly was after being nabbed with the 43rd selection of the 2010 draft for only $800,000. Now 20, the right-hander spent most of the 2012 pitching as a teenager in the double-A Southern League.

The first thing you notice when watching Walker pitch is his frame. He has a perfect pitcher’s frame and is very athletic. He fields his position very well and that athleticism should eventually allow him to develop above-average command, although it’s currently inconsistent. He has a low-stress delivery and easy velocity; he looks like he’s playing catch with the backstop. He stands very tall, stays back well over the rubber and maintains good balance.

Walker has a fastball that sits in the mid-to-upper 90s but I did not seen premium movement. With that said, hitters either don’t pick up the ball well or there’s some late movement that keeps the ball off the sweet spot on the bat. When I saw him pitch he was certainly favoring the fastball while sprinkling in curveballs and the very occasional changeup. He did slow his arm down a bit when he threw some of his breaking balls. Hitters either don’t pick up the ball well or there’s some late movement that keeps the ball off the sweet spot on the bat

Walker’s numbers on the season were skewed by a particularly bad June, where he posted a 9.15 ERA. His overall numbers were good, but not great, and he deserves credit for being the youngest pitcher in the league. I’d probably start him off back in double-A to begin the year but wouldn’t be shocked if he was assigned to triple-A instead. He could be in the major league rotation before his 21st birthday and has the ceiling of a No. 2 starter.

#3 Danny Hultzen (P)

Age G GS IP H HR K/9 BB/9 ERA FIP 22 25 25 124.0 87 4 9.87 5.44 3.05 3.41

The second overall pick of the 2012 draft, Hultzen ascended through the minors quickly, reaching triple-A after just half a season in pro ball. Unfortunately, he struggled mightily with his control after the promotion and walked 43 batters in 48.2 innings. It’s an entirely new issue for the U of Virginia alum, as he displayed at least average control in both college and double-A.

Hultzen has excellent zip on his fastball for a lefty and it sits 88-93 mph and touches the mid-90s when he reaches back for a little extra. His changeup can be deadly when he can set it up. He shows the same arm speed and action on both his fastball and changeup. When I saw Hultzen pitch at the triple-A level in August, his slider was inconsistent but showed a nice break.

While watching him, it was clear that he was struggling with his fastball command. When the ball was wandering, the southpaw was getting ahead of his arm and dragging his arm behind him. Hultzen also does a pronounced knee bend during his delivery and he was bending shortly before beginning his wind-up and that seemed to be messing up his balance. In speaking with a talent evaluator familiar with Hultzen it sounded as though there wasn’t too much concern over his struggles. “Danny is just going through the process becoming a big league pitcher. He just has to be able to command all his pitches and throw them for strikes,” he said. “I would also like to point out that it was his first full year. Learning to pitch is definitely a process.”

He will almost certainly return to triple-A to open the 2013 season and all eyes will be on his ability to control the strike zone. If he can iron out his issues, Hultzen could be ready for the majors around mid-2013. If everything clicks, Hultzen has the ceiling of a No. 2 starter.

#4 Nick Franklin (2B/SS)

Age PA H 2B HR BB SO SB AVG OBP SLG wOBA 21 625 155 38 13 60 121 15 .282 .354 .459 .366

The best non-pitching prospect in the Mariners system, Franklin isn’t overly physical but he has a stronger lower half and shows a wide, well-balanced base at the plate. The ball jumps off his bat, but I’d like to see him hit fewer fly balls and more line drives. He slugged 23 home runs at the A-ball level in 2010 but is not a true home-run hitter and will likely pop 10-15 homers at the big league level with a large collection of two-baggers.

Franklin isn’t as strong defensively as currently big league shortstop Brendan Ryan but he offers much more upside with the bat. The prospect could eventually push Ryan to a back-up role or send him out of town. Franklin is reliable at shortstop, fielding everything hit to him, and has good actions but both his range and arm are fringe-average for the position. Second base would probably be his best position but Dustin Ackley is far more secure in his job than Ryan.

A strong 2012 Arizona Fall League helped Franklin make up for a modest second half of the season at the triple-A level where he posted an 83 wRC+. Seattle will likely open the 2013 season with Brendan Ryan at shortstop but Franklin could emerge from the minors by mid-season.

#5 James Paxton (P)

Age G GS IP H HR K/9 BB/9 ERA FIP 23 26 26 119.0 110 6 9.53 4.54 3.33 3.28

Paxton has a ceiling close to that of Danny Hultzen but he also struggles with his control, having walked 54 batters in 106.1 double-A innings in 2012. He shows above-average, easy fastball velocity for a southpaw and has a tall, sturdy frame with a strong lower half and should be capable of providing tons of innings as a No. 3 starter in the starting rotation. He also has a very good curveball with plus potential and has worked to improve his changeup, which projects to develop into an average offering.

In watching Paxton pitch, I noticed that he throws with a high-three-quarter delivery with deception. He keeps the ball hidden well and has a distracting delivery thanks to a lot of extranious arm movement. But he also doesn’t have the most controlled delivery so it’s easy to see why he struggles with both his command and control. On the plus side, there isn’t much effort to his delivery. He was quite slow and deliberate from the stretch with pronounced arm action. Because of that, I wouldn’t be surprised to see him struggle at holding runners at the big league level.

After a solid double-A season in 2012, Paxton made another five starts in the Arizona Fall League with modest results. He should be ready for the triple-A test in 2013 but could see major league action in the second half of the year.

#6 Carter Capps (P)

Age G GS IP K/9 BB/9 GB% ERA FIP WAR 21 18 0 25.0 10.08 3.96 40.6 % 3.96 2.17 0.5

Capps was utterly dominating when he came out of the bullpen at the MLB level in 2012. He was hitting 98-99 mph with late movement in October. Along with his fastball, Capps also possesses an average slider and a changeup that he rarely throws. He has a strong, durable frame and throws with a three-quarter arm slot. There is not a ton of effort in his delivery when you consider how hard he throws.

Capps, 22, works up in the zone more than I’d like and he also gets hit rather hard at times — posting a line-drive rate of more than 27% in the majors — likely due to his lack of reliable secondary pitches. His control is currently better than his command.

A former supplemental third round pick out of a division II college in 2011, Capps zoomed through the minors and reached the majors in his first full season. The right-hander should have a spot in the Mariners’ bullpen to open 2013. He has the potential to develop into a high-leverage reliever and could rack up saves in Seattle for years to come.

#7 Brandon Maurer (P)

Age G GS IP H HR K/9 BB/9 ERA FIP 21 24 24 137.2 133 4 7.65 3.14 3.20 3.05

Maurer improved his stock more so than any other pitcher on the Top 15 list between 2011 and 2012. Prior to last year, he had never made more than 13 starts in a season during his four-year career and saw his innings almost double from 79.1 to 137.2 over the past two seasons. A big, strong-bodied right-hander, Maurer will look to put his checkered injury history behind him as he looks to build on his breakout performance with a promotion to triple-A to open 2013.

The former 23rd round draft pick should settle in nicely at the big league level as a No. 3 or 4 starter. He features a four-pitch mix, which includes a fastball that works in the low 90s and can hit the mid-90s. He also has a curveball, slider, and changeup. His slider has plus potential while his changeup needs to most polish. Maurer has the potential to develop both above-average command and above-average control of his repertoire but is a little behind the eight-ball because of all the missed time.

When I saw Maurer pitch he flashed all his secondary pitches and set them up well by establishing his fastball early in the count. With a three-quarter delivery, the right-hander pounded the lower half of the strike zone but got hit hard when he elevated the ball. He was able to get swings and misses on his breaking stuff. He worked quickly but was falling forward ahead of his arm at times.

#8 Brad Miller (SS)

Age PA H 2B HR BB SO SB AVG OBP SLG wOBA 22 643 185 40 15 74 105 23 .332 .408 .510 .406

A left-handed hitting shortstop with a plus hit tool and average power is extrememly valuable. Miller, 23, was a second round draft pick out of Clemson University in 2011 and he reached double-A in just his first full pro season.

A .341 career hitter, the infielder has enjoyed playing in some favorable hitting environments, which may have skewed his numbers to a degree, but he has shown the ability to control the strike zone quite well. His low-maintenance approach at the plate and swing give hope that he’ll maintain his offensive success as he moves up the ladder. A contact I spoke with about Miller said he has not been surprised with the shortstop’s success in pro ball because he’s a hard worker and dedicated to his craft. “As a hitter he has pretty good hand-eye coordination,” the talent evaluator said. “He just needs to get stronger and gain more experience.”

The big question with Miller is whether or not he’ll be able to stick at shortstop. He is athletic and shows good fielding actions but his throwing leads to numerous errors. He may end up at either third base or shortstop, but could offer enough offense for either position — even if his power is not quite ideal for the hot corner. Miller hit very well in 40 double-A games in 2012 but could return there to begin the coming season. If he continues to swing the bat like he has, he could reach Seattle by the end of 2013. A glut of infielders in the upper levels of the system and majors, though, could slow down his timetable.

#9 Stefen Romero (2B)

Age PA H 2B HR BB SO SB AVG OBP SLG wOBA 23 564 182 36 25 28 82 12 .351 .390 .592 .428

I’ll admit it: When I first started following Romero’s 2012 season I thought it was a fluke brought on by the hitting environment in the California League. However, he never stopped hitting – even after a promotion to double-A (.347 average) and then on into the Arizona Fall League (.333). I recently asked a talent evaluator about the prospect and he said, “Stefen Romero is just a solid player, a very advanced hitter. “He just needs to continue to play games to continue to progress.”

When I saw him play, he showed solid bat speed and a very nice level swing. He had a straight-away stance at the plate with a wide base. The opposition was pitching him in on the inner half of the plate but he did a nice job of waiting for his pitch to come out over the heart. He doesn’t use his legs much in his swing but has very quick hips that help generate his above-average power.

The big question with Romero is: Where is he going to play on the field? He’s played mostly second base as a pro, although he’s also dabbled at third base and in left field. He’ll probably never be a great second baseman – maybe not even average – but his bat should continue to carry him. Perhaps a super-sub role, similar to former Oakland A’s player Tony Phillips, is in his future.

#10 Victor Sanchez (P)

Age G GS IP H HR K/9 BB/9 ERA FIP 17 15 15 85.0 69 5 7.31 2.86 3.18 3.65

Sanchez, arguably the top international arm available in 2011, is a massive man-child who already tips the scale at more than 250 lbs (He’s only 6-feet tall). The right-hander has an advanced approach and feel for pitching, posting a walk rate of just 2.86 BB/9 during his pro debut against competition much older than himself. His strikeout rate was modest in part because he has yet to develop a reliable breaking ball but he possesses a couple of impressive weapons. As a talent evaluator stated, “He has very good fastball and has a feel for his off-speed, as well, which is pretty uncommon for a kid so young.” Sanchez should open the 2013 season in full season ball but will probably spend the entire year there. His ceiling is immense and it would be tempting to try and accelerate his timetable but there is a lot of pitching depth ahead of him.

#11 Patrick Kivlehan (3B)

Age PA H 2B HR BB SO SB AVG OBP SLG wOBA 22 316 85 17 12 19 93 14 .301 .373 .511 .410

A fourth-round selection out of Rutgers University in 2012, Kivlehan has impressed the Mariners front office with his potential. The infielder may have more upside than the typical 22-year-old college senior because he focused primary on football during his collegiate career and did not play baseball until this past season. Despite his inexperience on the field, Kivlehan’s athleticism has helped him succeed in the bowels of the minor league system.

He posted a 152 wRC+ with above-average power output in 72 games. On the down side, the New York state native is very aggressive at the plate and needs time to improve his pitch recognition and learn how to identify and wait for his pitch. He struck out at a rate of 29% with a walk rate of just 6%. Kivlehan is very raw in the field and may not have enough development time to play catchup (because his bat is more advanced, and his age is not on his side), which could result in a position switch. Because of his raw edges, he could open 2013 at Clinton in the Midwest League with a quick promotion to the high-A California League in mind.

#12 Gabriel Guerrero (OF)

Age PA H 2B HR BB SO SB AVG OBP SLG wOBA 18 305 96 14 15 24 41 4 .349 .393 .593 .450

You’re going to get some press when your uncle is Vladimir Guerrero but with Gabriel the attention is warranted for his own abilities on the field. He’s raw but projectable and should add strength to his slender frame, which could help his power blossom. He already shows a quick bat and makes solid contact. Like his uncle, the young hitter is aggressive — although not to the same crazy degree. The 19-year-old prospect opened the 2012 season in the Dominican Summer League and hit .355 with 11 home runs. That earned him a late promotion to the Arizona League for his first taste of North American ball. He again hit more than .300 and added four long balls in 18 games. Guerrero won’t reach Seattle any time soon but his ceiling is perhaps higher than any bat in the system.

#13 Tyler Pike (P)

Age G GS IP H HR K/9 BB/9 ERA FIP 18 11 11 50.2 34 1 10.13 3.73 1.78 2.75

A projection pick from the 2012 amateur draft, Pike was signed away from a commitment to Florida State University. The 18-year-old southpaw showed a little more polish than expected when he posted a 1.78 ERA and allowed just 34 hits in 50.2 rookie ball innings. He struck out 57 batters but walked 21. Pike, a Florida native, will need to improve both his command and control as he moves up the ladder. His repertoire includes a high-80s fastball, curveball and changeup. He currently projects to develop into a No. 4 starter.

#14 Stephen Pryor (P)

Age G GS IP K/9 BB/9 GB% ERA FIP WAR 22 26 0 23.0 10.57 5.09 37.1 % 3.91 5.27 -0.3

Pryor, 23, is another hard-throwing reliever that debuted with the Seattle Mariners in 2012. He doesn’t have the same easy velocity that Carter Capps possesses, and his delivery is also not as fluid or easy. He has a strong frame and should be durable. His control has fluctuated throughout his career and needs polishing before he realizes his potential.Pryor reached the majors in just his third pro season. He played at four levels and could open 2013 with Seattle as a middle reliever. Eventually, he should have the ceiling of an eighth-inning reliever.

#15 Timmy Lopes (2B)

Age PA H 2B HR BB SO SB AVG OBP SLG wOBA 18 256 71 11 0 24 30 7 .313 .375 .476 .385

Lopes, 18, showed some late advancement in high school, which convinced the Mariners to sign him away from a commitment to UC Irvine. The middle infielder immediately took to pro ball and hit more than .300 with gap power in rookie ball. A contact I spoke with was not surprised at his early success. “I would think having older brother (Christian Lopes, 2011 7th rounder) who just went through al lot of the same things has helped him with the transition.” Both brothers have a shot at developing into an everyday second baseman at the big league level with Timmy having the higher ceiling.

Originally a shortstop in high school, Lopes moved to second base as a pro, although he did appear in seven games at his natural position. “His defense at second base is pretty good,” the contact said, although cautioning:. “[He] will need to continue to work on all aspects of his game.” Lopes shows good actions in the field and solid range but his arm strength is below average for a shortstop. The organization gave him a vote of confidence at the end of the regular season by allowing the California native to appear in four games in high-A ball. He should open 2013 in full-season ball, although likely in Clinton.