Hired as Mariners general manager in September 2015, Jerry Dipoto has since shaken up the team's big league roster and farm system by making 36 trades, far and away more than any other GM during that stretch. It yielded immediate and promising results for the franchise in 2016, when the Mariners battled for an American League Wild Card spot for much of the season en route to an 86-76 overall record and a second-place finish in the AL West.
The Mariners' system as a whole also took a considerable step forward thanks to an organization-wide emphasis on controlling the strike zone and improving contact rates under the guidance of new farm director Andy McKay. All six of Seattle's Minor League affiliates reached the postseason in their respective leagues, with Double-A Jackson and the club's Rookie Arizona League affiliate winning titles.
• Mariners' Top 30 Prospects list
:: Team Top 30 Prospects lists ::
No Mariners farmhand made greater strides last season than outfielder and current MLBPipeline.com No. 36 overall prospectTyler O'Neill, who hit .293 with 24 homers and a Double-A Southern League-leading 102 RBIs to garner the circuit's MVP award. He ranks as the club's No. 2 prospect behind 2016 Golden Spikes Award-winner Kyle Lewis (No. 29 overall), Seattle's first-round pick last June who impressed during his pro debut before blowing out his right knee in a home-plate collision in July.
Meanwhile, Dipoto's activity on the trade front has given the Mariners' new Top 30 prospects list a much different look than a year ago. In total, seven of Dipoto's acquisitions appear on this year's list, a group that includes three Top 10 prospects in Mitch Haniger, Max Povse -- part of the trade that sent 2014 first-round pick Alex Jackson to Atlanta in November -- and Dan Vogelbach, as well as big leaguers Ben Gamel, Rob Whalen, Dillon Overton and James Pazos.
Biggest jump/fall
Here are the players whose ranks changed the most from the 2016 preseason list to the 2017 preseason list.
Jump: Dan Altavilla (2016: 20 | 2017: 9)

Fall: Boog Powell, OF (2016: 8 | 2017: 26)
Best tools
Players are graded on a 20-80 scouting scale for future tools -- 20-30 is well below average, 40 is below average, 50 is average, 60 is above average and 70-80 is well above average.
Hit: Kyle Lewis (55)
Power: Kyle Lewis and Tyler O'Neill (60)
Run: Drew Jackson and Braden Bishop (65)
Arm: Drew Jackson (70)
Defense: Braden Bishop (65)
Fastball: Thyago Vieira (80)
Curveball: Rob Whalen (55)
Slider: Dan Altavilla (60)
Changeup: Nick Neidert (60)
Control: Andrew Moore (60)
How they were built
Draft: 14
International: 7
Trade: 9
Breakdown by ETA
2017: 15
2018: 4
2019: 7
2020: 4
Breakdown by position
C: 1
1B: 1
2B: 1
3B: 2
SS: 3
OF: 8
RHP: 11
LHP: 3
Here's a look at the Mariners' preseason Top 10 prospects from each of the past seven years (click here to see a larger image):