This was Bryant's first game at third base since March 12 after being sidelined with fatigue in his right shoulder. It hasn't affected his hitting. Bryant also hit two homers on March 12, and again on March 14.
Bryant launched No. 8 with two on and one out in the fourth off Kevin Correia. On Thursday, he hit another home run in a "B" game, but that doesn't count in the spring statistics.
But the Mariners ace brushed off the poor outing and said it was just part of the process of getting ready for Opening Day.
"It's part of the game," Hernandez said. "I definitely didn't have the results I wanted, but I got my work in and threw a lot of pitches. That's what I'm here for."
Asked about Bryant's homer, Hernandez said: "Big power. Nice. He looked good at the plate. He hit bad pitches. It's Spring Training."
The Mariners took advantage of two outfield miscues to tally in the third. Brad Miller reached second on a double that center fielder Dexter Fowler lost in the sun, and then scored on right fielder Jorge Soler's error as he couldn't get his glove on Austin Jackson's fly ball. Jackson then tallied on Robinson Cano's groundout. Nelson Cruz followed with a solo homer to tie the game at 3.
Anthony Rizzo hit a go-ahead RBI double with two outs in the Cubs third and then scored on Russell's homer, his first this spring, which chased Hernandez. Welington Castillo, who hit a RBI double in the second, added a solo shot leading off the fourth.
In the eighth, Seattle's Austin Wilson hit a three-run, inside-the-park homer off Andres Santiago, scoring Jordy Lara and Chris Mariscal, after the ball got by Junior Lake in left-center.
The Cubs rank among the Major League leaders with 28 home runs this spring.
Up next: Jason Hammel will make his fourth spring start Sunday as the Cubs play host to the Padres at Sloan Park in Mesa. Expect to see plenty of clean-shaven Cubs, including manager Joe Maddon as they take part in a "Respect Bald" event to raise money for the battle against pediatric cancer. Maddon and others will have their heads shaved at 1:30 p.m. CT on Field 1 at the Cubs complex. Fans can participate by donating $100 to get their heads shaved alongside the players. Besides the trim, fans will receive a T-shirt. Sunday's game will be broadcast on Comcast SportsNet and WBBM Radio, starting at 3:05 p.m. CT.
Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.