"I think he has taken the next step," McClendon said Tuesday. "I think he's one of the top third basemen in the league. And rightfully so. He's played extremely well on both sides of the ball. And I think he's only going to get better."
The 26-year-old hit his 25th home run in Monday's 14-4 loss to the Blue Jays, becoming the 15th Mariner to amass 25 doubles, 25 home runs and 90 RBIs in a season, and the first since Jose Lopez in 2009.
Seager already has the third-most RBIs for a Seattle third baseman in a season behind Jim Presley (109 in 1986) and Adrian Beltre (98 in 2007) and was tied for the fourth-most homers behind Presley (28 in 1985 and 27 in '86) and Beltre (26 in '07) entering Tuesday.
McClendon is equally pleased with Seager's glove work at the hot corner, where he's spent a lot of time this season with infield coach Chris Woodward.
"He's worked extremely hard," McClendon said. "Woody has done a great job with him as far as his preparation. His awareness of guys in the league and what they're capable of doing, his positioning is a lot better. And I think his feet are a lot better than they were in the past."
As for the bat? McClendon has said in the past that Seager has benefited from playing with Cano, but he was careful to note that it's the youngster himself that has done the work.
"Quite frankly, Seager was on the verge of becoming a very good player," he said. "I just think it's a natural progression for him from an offensive standpoint. He's gotten better. We've pushed and prodded him, and he's gotten better. But I think the credit goes to Seager because of the time and work he's put in."
Greg Johns is a reporter for MLB.com. Follow him on Twitter @GregJohnsMLB as well as his Mariners Musings blog. This story was not subject to the approval of Major League Baseball or its clubs.