DETROIT — The plot thickens regarding the Mariners’ depleted rotation.
Right-hander Taijuan Walker headed back Monday to Seattle to undergo a further examination, likely to include a magnetic resonance imaging (MRI) test, in an effort to find answers regarding the tendinitis in his right foot.
"We just want to make sure," manager Scott Servais said prior to Monday’s series opener against the Tigers. "He tested out OK today (in an examination by trainer Rick Griffin), but I think we’d all feel more comfortable if we had some pictures of it."
Walker made an early exit Sunday for a second straight start because of posterior tibial tendinitis — inflammation in the tendon that attaches the calf muscle to the bones on the inside of the foot.
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The Mariners had believed they could control the problem by taping his foot and ankle — which wasn’t done before he worked just 3 1/3 innings in a June 14 start at Tampa Bay.
But Walker lasted just five innings Sunday at Boston and was limping noticeably after the game. The Mariners led 1-0 when he departed, but the bullpen coughed up two runs in a 2-1 loss.
Walker’s return to Seattle dims the likelihood that he will make his scheduled start Friday against the St. Louis Cardinals at Safeco Field. He would likely need to throw a bullpen workout Wednesday without difficulty to gain clearance.
"Maybe we can figure out a way to jimmy the rotation to push him back a day or two," Servais said. "So maybe we wouldn’t have to DL him. I’m not sure. I don’t want to get ahead of myself."
Walker, 23, is just 3-6 despite a 3.45 ERA in 14 starts. His tendinitis stems from having flat feet, which heightens the stress he places on the arch in his right foot as he pushes off the rubber.
The Mariners are already operating without two of their five starting pitchers.
Right-hander Felix Hernandez hasn’t pitched since May 27 because of a strained right calf muscle. While he is expected to begin throwing this week from flat ground, he isn’t likely to rejoin the rotation until after the All-Star break.
Lefty Wade Miley is nursing an impingement in his shoulder, which forced him to the disabled list prior to last Friday’s game at Boston. The Mariners were able to backdate the injury to June 13, but Miley is unavailable until at least June 28.
"It’s tough," Servais admitted. "We will get Wade back. That helps. Felix is feeling better. Good report today. Moving in the right direction.
"But, yeah, it’s disappointing and disheartening, especially if Taijuan is going to be down for any amount of time."
Having already summoned James Paxton and Adrian Sampson from Triple-A Tacoma to patch their rotation, the Mariners could have just-acquired Zach Lee atop their list of alternatives if Walker can’t start Friday against Cardinals.
The Mariners obtained Lee from the Los Angeles Dodgers in a late Sunday trade for shortstop Chris Taylor.
While the Mariners assigned Lee, a right-hander, to Tacoma, he is on the 40-man roster, which means he can be recalled to the big leagues without the need for a corresponding space-clearing move.
Right-hander Donn Roach pitched eight scoreless innings Sunday for Tacoma but is not on the 40-man roster. Nor is right-hander Joe Wieland. Right-hander Cody Martin is on the roster, but he was scheduled to start Monday at Sacramento.
Lee, 24, was 7-5 with a 4.89 ERA this season in 13 starts at Triple-A Oklahoma, but 10 runs came in one start. He hasn’t pitched since Thursday, when he limited Omaha (Royals) to two runs in seven innings.
"I know he was quite a prospect when he first came out of high school," Servais said. "I think he’s had a pretty good minor-league track record. It’s an opportunity, a change of scenery for him and a change of scenery for Chris Taylor.
"So it’s a good trade for the players. We’ll see how it works out for the teams."
Hi-A Bakersfield right fielder Chantz Mack hit for the cycle Sunday while going 5-for-6 and driving in five runs in a 12-2 victory at Lancaster (Astros).
Mack, 25, had a single in the first inning, struck out in the third, a leadoff triple in the fifth, a two-run double in the sixth, a three-run homer in the seventh and a double in the ninth.
The five RBIs boosted Mack’s season total to 57, which leads the California League. He is also batting .304 with eight homers in 65 games.
The Mariners selected Mack in the 29th round of the 2013 draft.
Three of the Mariners’ four full-season affiliates closed out their first-half seasons Sunday. All full-season leagues below Triple-A reset their standings in the second half.
A year ago, all four of the organization’s full-season affiliates finished with losing records. This year, all four have winning records through Sunday. Two have clinched postseason berth, and another is in first place.
***Triple-A Tacoma: 39-30, first place by one game in the Pacific Coast League Pacific Northern Division. Played Monday night at Sacramento (Giants). Finished last season at 68-76.
***Double-Jackson: 46-24, won the pennant in the Southern League North Division by 10 games. Set franchise record for victories in a half season. Finished last season at 53-84.
***Hi-A Bakersfield: 37-33, third place in the California League North Division. Have won 15 of their last 20. Finished last season at 61-79.
***Lo-A Clinton: 39-31, second place in Midwest League Western Division. Won wild-card berth. Finished last season at 46-93.
It was two years ago Tuesday — June 21, 2014 — that the Mariners stung Kansas City with a game-winning rally in the ninth inning for a second straight game.
Dustin Ackley’s two-out RBI single against former Mariner Jason Vargas provided the winning run in a 2-1 victory. The Mariners scored two runs in the ninth inning the previous night in a 7-5 victory.
It marked the first time in nearly five years — July 3-4, 2009 at Boston — that the Mariners won back-to-back road games in their final at-bat.
First baseman Adam Lind entered Monday with eight homers in his last 79 at-bats after starting the season with on homer in 92 at-bats…rookie reliever Edwin Diaz has 11 strikeouts over 7 2/3 innings in his five appearances…center fielder Leonys Martin has a 1.113 OPS (on-base percentage plus slugging percentage) since May 18. Only three players with at least 50 plate appearances are better in that span: Boston DH David Ortiz (1.218), Kansas City catcher Salvy Perez (1.131) and St. Louis third baseman Matt Carpenter (1.126).
The Mariners and Tigers continue their four-game series at 4:08 p.m. Pacific time Tuesday at Comerica Park in Detroit.
Left-hander James Paxton (1-2 with a 2.86 ERA) will face Detroit right-hander Justin Verlander (7-5, 3.87). The game can be seen on Root Sports Northwest and heard on 710 ESPN.
Bob Dutton: @TNT_Mariners