SEATTLE — Call it a small setback. At this point, the Seattle Mariners believe all outfielder Mitch Haniger needs is a day or two of rest before he’s able to proceed with plans to begin a minor-league rehab assignment.

Haniger said he felt some tenderness Thursday in his strained right oblique after a series of pre-game drills. He suffered the injury April 25 at Detroit.

The Mariners aren’t taking any chances. Haniger had been scheduled to depart this weekend to begin a rehab assignment, but oblique strains are notoriously easy to aggravate.

“He probably got a little too aggressive (Thursday),” manager Scott Servais said. “So we’re just going to give him a day off and slow him down a little bit. He felt a little tender at the end of the workout. Nothing totally alarming.

“But it was like, ‘OK, let’s just slow down here a second,’ instead of shooting him out, and he’s in a competitive situation.”

Haniger, 26, batted .342 with four homers and 16 RBI in 21 games prior to the injury and remains well ahead of the typical recovery period of four-to-six weeks for a grade 2 strain.

“Mitch wants to push the envelope as much as anybody,” Servais said, “but he didn’t feel quite right after (Thursday). He did quite a bit (Thursday). He threw to the bases. He ran. He took BP. So we’ll just slow down a little bit.”

— Lefty James Paxton experienced no day-after problems from a 25-pitch bullpen workout Thursday in his recovery from a strained forearm muscle. He is scheduled to throw another bullpen workout Sunday before departing on a rehab assignment.

While plans call for Paxton to make only one rehab start, he isn’t expected to join the Mariners on an eight-game trip that begins Tuesday in Washington.

“That might be stretching it,” Servais said. “Maybe when we come back off the road might be more realistic.”

The Mariners return home May 31 for an 11-game run at Safeco Field against Colorado, Tampa Bay, Minnesota and Toronto.

Fixing Diaz

Having identified what they believe to be the problem with struggling closer Edwin Diaz, the Mariners are now looking for the best situation for him to test his adjustments in a game situation.

That could come as soon as Friday’s game against the Chicago White Sox at Safeco Field.

“You might see him right after the starter,” manager Scott Servais said in his daily pre-game news briefing. “You might see one of the length guys, then Diaz. I don’t want to look up and have him as the only guy standing in the ninth inning.

“We somehow need to get him in a less-leveraged situation.”

The Mariners pulled Diaz out of his closer duties after he nearly squandered a three-run lead Monday in the ninth inning before Tony Zych closed out a 6-5 victory over Oakland.

That was one day after Diaz surrendered a walk-off homer to Kevin Pillar in a 3-2 loss at Toronto.

A sensation a year ago as a rookie, Diaz now sports a 5.28 ERA and has issued 10 walks in his 15 1/3 innings. The Mariners believe the problem is he is rushing through his delivery.

That led to a series of sessions this week with pitching coach Mel Stottlemyre Jr.

Servais said, “He’s starting to get a feel and understanding for staying back over the rubber. His mechanics … he rushes through so quickly that his arm can’t catch up. That’s where the straight fastballs come from.”

It’s an easy fix — in theory.

“You can practice it on the side all you want,” Servais said. “When the adrenaline starts, and you’re on the mound, then you’ve got to see if you can put it in play.”

Hit machine keeps churning

There are times when Mariners shortstop Jean Segura seems to believe he can hit any pitch no matter where it’s thrown. And there are times, like now, when he pretty much does just that.

Segura carried a career-best 17-game hitting streak into Friday’s game against the Chicago White Sox at Safeco Field. He also led the American League in batting with a .359 average.

“He’s an interesting player,” manager Scott Servais said. “Every night, you learn a little bit more about him. It’s hits. It’s home runs. It’s stolen bases. It’s defense. It’s all over the field. It’s something a little bit different every night.”

Segura hit a three-run homer in Thursday’s 5-4 victory over the White Sox in the series opener. He received an intentional walk in the ninth inning just prior to Guillermo Heredia’s game-winning RBI single.

This isn’t a total surprise.

Segura, 27, blossomed last season at Arizona into one of the game’s top hitters when he batted .319 and led the National League with 203 hits before coming to the Mariners in a blockbuster November trade.

“Everything is working well for me right now,” he said. “I feel lucky. It’s not easy to do. I just want to keep it simple. Just go out there and focus every at-bat. You know that’s what it going to take.”

That intentional walk Thursday is pretty much the only way to pitch around Segura, who controls the strike zone (and beyond) with quick hands and a short swing.

“Sometimes he gets in trouble,” Servais said, “because he thinks he can hit every pitch, but he has some kind of hand-eye coordination. He’s fun to watch hit.”

On deck

The Mariners and White Sox continue their four-game series at 7:10 p.m. Saturday at Safeco Field. Right-hander Yovani Gallardo (2-3 with a 4.53 ERA) will face Chicago right-hander Mike Pelfrey (0-4, 5.70).

The game can be seen on Root Sports Northwest and heard on 710 ESPN and the Mariners Radio Network.