Beyond that is to be determined.

The longtime Seattle Mariners ace is struggling this season with an 8-9 record and a career-worst 5.58 ERA in 21 starts.

Hernandez is coming off what he called an "embarrassing" outing in which he gave up seven runs in 2 2/3 innings in an 11-5 loss Saturday to the Los Angeles Angels.

After much discussion, general manager Jerry Dipoto and manager Scott Servais decided the right-hander will start when the Mariners open a four-game series against the visiting Toronto Blue Jays.

"Really important," Dipoto said of the Mariners' need for Hernandez to pitch like the King Felix of old in their push for their first postseason berth since 2001 -- the longest drought in the four major professional sports. "And to that extent, obviously on Thursday, hopefully we get beyond where he's been, particularly this last start. The Mariners have relied on Felix to take the ball, we're going to rely on him again on Thursday and we're going to take it day by day and just see where we are as a team."

In other words, six All-Star seasons and the 2010 American League Cy Young Award won't be enough to keep Hernandez in the rotation for the final two months of the regular season unless he produces.

"At the end of the day, we are here to win the games," Dipoto said. "And I think that it's obvious, by the fact that we are making these (trade deadline) moves, we know we're in this, we're doing our best to maintain our position and we're going to be conscious of the wins."

As for the playoff chase, Seattle dropped into a tie with Oakland for the American League's second and final wild-card berth with an 8-3 loss Wednesday to Houston.

That increases the need for the Mariners to get some productive starts out of Hernandez, who spent 10 days on the disabled list in July with lower back stiffness.

"I hope he gets it turned around. We certainly need him," Servais said. "He wants to be a part of this, there's no question about that. But you've got to go out and do it."

Hernandez is 7-6 with a 4.02 ERA in 17 career starts against the Blue Jays, the last coming in 2016.

The Blue Jays, who were swept in a three-game series in Oakland, hadn't yet announced a starter for the opener in Seattle by the time their 8-3 loss to the Athletics ended Wednesday afternoon.

Toronto will be without infielder Lourdes Gurriel Jr., who was batting .322 with seven home runs and 22 RBIs in 38 games this season. The rookie will miss two to six weeks weeks with a high left ankle sprain and a Grade 1 left knee sprain suffered Sunday while sliding awkwardly into second base against the Chicago White Sox.

"We don't know exactly how long it will be, but those ankles can be a little bit tricky," Blue Jays manager John Gibbons said. "So it's best to let it heal up and get back to his normal self. The timing of it couldn't be worse because of what he was doing."

Closer Ken Giles, acquired in a trade Monday for the suspended Roberto Osuna, is scheduled to join the Blue Jays in Seattle.