DETROIT -- It was another day, another newcomer on Thursday for the Mariners as left-handed reliever Taylor Guilbeau was called up from Triple-A Tacoma for the afternoon series finale against the Tigers, with Seattle continuing its record-setting pace for players used in a season.

Guilbeau replaced right-hander Brandon Brennan, who returned to the 10-day injured list with right shoulder inflammation. Guilbeau will be the 62nd player employed by the Mariners this season, which is just two shy of the Major League-record 64 players used by the Rangers in 2014.

Guilbeau will be the 40th pitcher used this season by Seattle, which ties the MLB record set by the ’14 Rangers and tied by the Mariners in ’17.

The Mariners figure to zoom past both those numbers in the final six weeks of the season, given that a handful of young prospects are expected to be called up when rosters can be expanded in September.

“Forty pitchers and we’re not done,” manager Scott Servais said with a shake of his head. “It’s the year of opportunity.”

Guilbeau, 26, was one of three pitchers acquired from the Nationals at the July 31 Trade Deadline in exchange for relievers Roenis Elias and Hunter Strickland. He will be the 16th Mariner to make his MLB debut this season once he gets in a game.

The 6-foot-4, 180-pounder posted a 1.80 ERA with five strikeouts and two walks in five innings over five relief appearances for Tacoma. He is the Mariners’ No. 22 prospect, per MLB Pipeline.

The Louisiana native flew with the Rainiers from New Orleans to Seattle on Wednesday before being told he needed to catch a red-eye flight to Detroit to join the Mariners. He landed in Michigan at 5 a.m. ET and slept for two hours in the visitor’s clubhouse at Comerica Park before meeting his new teammates as they arrived for the series-ending day game.

“I’m ready to go,” Guilbeau said. “This is awesome. I’ve been dreaming about putting on a big league uniform ever since I was 5 years old.”

Overall this season, Guilbeau is 3-2 with a 2.77 ERA in 39 relief outings for three Minor League teams, having pitched for Triple-A Fresno and Double-A Harrisburg for the Nationals. He was a 10th-round Draft pick by the Nats in 2014 out of Alabama.

Brennan lands back on the IL after just three outings since he was activated on Aug. 6. The 28-year-old Rule 5 rookie was pulled after just two pitches in his last outing Tuesday against the Tigers after feeling fatigue in his right shoulder.

Brennan fell victim to the timing game, as he’s only expected to need a couple days of down time, but the club needs a complete relief crew with openers scheduled to pitch Thursday and Friday, followed by a full bullpen day on Saturday when the plan is to employ relievers rather than promote a fifth starter from the Minors.

Due to the number of off-days in the schedule, the Mariners had been able to use just four starters since trading Mike Leake to the D-backs on July 31. Brennan will be eligible to come off the 10-day IL the final week of August, but he likely will be held out until rosters can be expanded in September.

“They need as many fresh arms as possible, and since I need a couple days, it’s just bad timing for me,” Brennan said. “I was hoping for just a couple days and come back, but the way the schedule lies, that’s just the way it is.”

In 33 appearances with the Mariners this season, Brennan is 2-6 with a 5.50 ERA.

Worth noting

• Veteran right-hander Felix Hernandez threw four scoreless innings while allowing just one hit with no walks and eight strikeouts on Wednesday for Class A Short-Season Everett in his third rehab outing as he works back from a three-month absence due to right shoulder issues.

Servais said Hernandez will make at least one start in five or six days for Tacoma and then potentially be ready to rejoin the Mariners.

"He threw a lot of strikes. His arm felt great coming out of the game,” Servais said. “It's definitely the most positive report we've got about Felix so far, which is awesome."

• Mitch Haniger went 0-for-2 with a walk while playing right field in his second rehab game with Class A Advanced Modesto on Wednesday, and Braden Bishop was 0-for-4 at designated hitter in his rehab debut. Haniger will play one more game on Thursday in a DH role with the Cal League team before moving to Tacoma, while Bishop will play in the outfield on Thursday and could remain longer with the Nuts.

• Outfielder Julio Rodriguez, the Mariners’ No. 2 prospect per MLB Pipeline, is being promoted to Modesto for the final weeks of the regular season. The 18-year-old hit .293/.359/.490 with 10 homers and 50 RBIs in 67 games for Class A West Virginia.