Kyle Seager has grown into a foundation-level player for the Mariners

Kyle Seager never has been satisfied as a professional baseball player. Perhaps it stems from being largely overlooked in college and later as a Mariners minor-leaguer. Once projected by scouts to be a utility infielder, the third baseman has made himself into a foundation-level player for the Mariners. He has performed at an All-Star level the past three seasons and only seems to be getting better.

The Mariners wisely locked him up with a seven-year contract extension before the 2015 season. And at age 29, he will be a cornerstone for the team going forward.

Here is our spring-training position preview for third base. Pitchers and catchers report to spring training in Peoria, Ariz., on Feb. 14.

The past

Seager put together another outstanding season, hitting .278 (166 for 597) with 36 doubles, three triples, 30 home runs, 99 RBI, a .359 on-base percentage and a .499 slugging percentage in 158 games. He posted a 5.5 Wins Above Replacement per Fangraphs, the highest of his career.

Here are a few more numbers …

• Seager set career highs in home runs with 30 (previous: 26, 2015), RBI with 99 (previous: 96, 2014), batting average at .278 (previous: .268, 2014), runs with 89 (previous; 85, 2015), OBP at .359 (previous: .338, 2013), slugging percentage at .499 (previous: .454, 2014), walks with 69 (previous: 68, 2013) and game-winning RBI with 11 (previous: 10, 2012). He finished with 36 doubles, one shy of his career best (37, 2015).
• Among American League third basemen, Seager tied for second in RBI (99), third in on-base percentage (.359), tied for third in runs (89), fourth in doubles (36), fourth in extra-base hits (69), fourth in OPS (.859), fifth in hits (166), fifth in slugging percentage (.499) and sixth in home runs (30).
• He led the American League in starts at third base (156) and led the majors in innings at third base (1399.2).
• He became the first Mariners third baseman with at least 35 doubles, 30 home runs and 90 RBI.
• Seager has increased his home-run total in each of his first six seasons in the majors (2011: 3, 2012: 20, 2013: 22, 2014: 25, 2015: 26 and 2016: 30). He is the first player in MLB to do so since Matt Kemp (2006-11). The only other Mariners player to accomplish this feat is Tino Martinez.
• In the past five seasons (2012-16), he has posted four seasons with 30-plus doubles & 20-plus homers, tied for the most such seasons in MLB during that time span with Robinson Cano, Josh Donaldson, Paul Goldschmidt and Mike Trout.
• Tied for first in the majors among left-handed hitters with Cano in home runs vs. left-handed pitchers with 11.

In a league with some outstanding third basemen, Seager ranks near the top in most categories.

The numbers are impressive, but they came despite Seager having an awful first month of the season and less than stellar last month. In the first 21 games, Seager hit .139 (11 for 79) with a three doubles, four homers, 10 RBI and 15 strikeouts. During that span, manager Scott Servais gave Seager a rare day off in New York on April 16 to clear his head. Seager seethed over being out of the lineup because of his struggles. But it might have helped in the long run.

After the first 21 games, Seager hit .317 (129 for 407) with a .945 OPS, 28 doubles, three triples, 21 homers and 76 RBI over the next 108 games. He didn’t sit again until Aug. 25-27 after fouling a ball off his foot. He hit a cold spell in the final 20 games, hitting .169 (13 for 77)  with a .550 OPS, three doubles, two homers and seven RBI. With every game needed in that stretch because of postseason implications, the Mariners couldn’t give Seager a much-needed rest.

After taking some criticism in 2015 for struggling with runners in scoring position, Seager silenced the critics in 2016. A simplified approach led to success. He hit .310 with a 1.031 OPS, eight doubles, 12 homers and 74 RBI with runners in scoring position. The 74 RBI were eighth-most in the AL. He also tied for fourth with the most two-out RBI with 43.

But it wasn’t all gumdrops and rainbows for Seager in 2016. Besides the slow start and less than ideal finish, he also went into a bit of a fielding funk. Seager committed 22 errors, most among AL third basemen. Many came on relatively simple ground balls to his left. The root of that problem stemmed from a footwork issue, which the Mariners identified and a frustrated and irritated Seager worked to address late in the season. Advanced metrics still considered Seager an upper-level third baseman. He saved 15 runs per the Defensive Runs Saved metric and had a 6.2 defensive WAR per Fangraphs.

Seager still made scores of outstanding plays. And there was this one that saved a game in Anaheim late in the season.

The present

So what should Mariners fans expect from Seager this season? It’s still odd to think of him as a 30-homer player. But maybe it’s time to expect that. He might not look like a traditional power hitter, but he certainly seems to be improving each season.  He’s seemed to find ways to improve as a hitter in almost every facet each season. Perhaps the next threshold is the .300 mark. Seager is capable of that, particularly with his improvement in driving the ball to the opposite field. He also has embraced the Mariners’ “Control the Zone” philosophy. He posted 69 walks and a .359 on-base percentage — both career highs. It helped him to be a more mature hitter.

Here’s his spray charts from Brooks Baseball …

2016

2015

Knowing Seager and his mind-set, much of the offseason and spring will be spent correcting any defensive deficiencies, particularly the issues going to his left. Part of what has pushed him to this level was to identify a weakness — real or perceived — and attack it with work to improve on it. He has done that with adding power, making plays on the slow roller up the line and conditioning his body to play 155-plus games.

The acquisition of Danny Valencia in the offseason will give Servais an added luxury. Seager rarely misses games, but when the Mariners had to sit him they were forced to play a light-hitting utility player at that spot. Valencia, a natural third baseman, will allow the Mariners to give Seager a day off if needed, or even “rest days” at DH and not see as large of a drop-off in production. If Seager suffers an injury, Seattle would have a viable replacement in Valencia. Seager believes he should play all 162 games, but Servais plans to give him more rest and DH days this season. The belief is it will keep Seager strong throughout the season.

The future

With the extension Seager signed before the 2015 season, he’s under contract through 2021 with an option in 2022. Seager is getting more expensive each year. The extension paid out his arbitration years. This would’ve been his final year of arbitration eligibility, and a $10.5 million salary is less than what he would have earned in arbitration based on his performance.

2017: $10.5 million

2018: $18.5 million

2019: $19 million

2020: $19 million

2021: $18 million

2022: $15 million/$20 million club option based on performance

By most standards, Seager has been a bargain the past three seasons. And given his work ethic and obsession with improvement, it’s difficult to see him slipping significantly in that window. He now finally is going to be paid at a level that matches his play.

Beyond Seager, the future third baseman in the organization might be Joe Rizzo. He’s a stocky infielder with a compact, left-handed swing, a mature approach at the plate and the potential for power. Sound familiar?

Rizzo, who the Mariners selected in the second round of last year’s draft out of Oakton (Va.) High School, hit .291 (43 for 148) with seven doubles, a triple, two homers and 21 RBI in 39 games in the Arizona Rookie League.