But while Lester has been shortchanged by an anemic offense, Hernandez has little to blame but his own ineffectiveness.
Hernandez (13-5, 2.23 ERA) gave up a season-high five earned runs over seven innings in an 8-3 loss to Washington on Friday. It was the third straight sub-par outing for the right-hander, who failed to complete six innings in each of his previous two after throwing seven-plus innings in 16 consecutive starts.
Lester (13-9, 2.55) is winless in his last three starts despite a 2.84 ERA in that span, receiving three total runs of support. The Oakland offense came up empty behind him in a 4-0 road loss to the Los Angeles Angels on Friday as he was charged with two earned runs in six innings.
Lester hasn't gone more than three starts without a victory since he was 0-4 in a six-start span from May 20-June 16, 2013. Hernandez has two winless stretches of four or more starts over the past two seasons.
The Seattle hurler hadn't lost at Safeco Field since June 13 prior to Friday, going 5-0 with a 1.40 ERA over his six previous starts there.
"Felix is human," bench coach Trent Jewett said. "We ask a lot of him and I think he is up for the challenge but he is human. And the other team is getting paid too. It's going to happen."
Hernandez could be primed to bounce back versus the Athletics, against whom he's 5-1 with a 1.97 ERA in the last seven matchups. Each of those have been quality starts, and he struck out nine over eight innings in a 3-2 victory on July 11.
Lester had received 18 runs of support in 21 2-3 innings while winning his first three starts with the Athletics.
"We're just not putting consistent games together on both sides of the ball," he told MLB's official website.
He gave up five runs and nine hits over five innings in his last start against Seattle, an 11-4 road loss with Boston on July 8, 2013. He went 3-0 with a 1.96 ERA in his previous three matchups with the Mariners.
After totaling four runs while being swept in four games by the Angels, Oakland has shown a little more pop in the first two games of this series. The Athletics recorded 11 hits in a 6-1 win Monday, then scored a combined five runs in the eighth and ninth innings Tuesday but the result was a 6-5 defeat.
"No matter what inning you score in, it was a one-run game. We're one swing of the bat away from winning it," said Derek Norris, who was 2 for 4 for the second straight game.
Oakland (79-59) has dropped five of six and is trying to avoid losing back-to-back home games for the first time since a six-game losing streak from April 21-May 7 - a skid that included three straight losses to the Mariners.
Seattle (74-63) remained within 1 1/2 games of Detroit for the league's second wild-card spot. James Paxton gave up two runs over 7 2-3 innings and Austin Jackson was 2 for 4 with two RBIs to improve to 7 for 16 over his last four contests. Logan Morrison has hit .370 during a 15-game road hitting streak after going 2 for 4.
Adam Dunn singled in a run as a pinch-hitter Tuesday and is 3 for 4 with three RBIs since joining the Athletics.