Aug. 16-- Aug. 16--DETROIT -- A perfect storm of an upper-body workout, too many pitches while warming up in an inning that wouldn't end, previous shoulder issues and the Mariners' desire to have a bullpen start Saturday in Toronto sent right-handed reliever Brandon Brennan back to the 10-day injured list Thursday with shoulder inflammation.

"After he played catch (Wednesday), he felt fatigued and didn't feel quite right," manager Scott Servais said. "With where we are at coming up on our schedule with a couple of games with an opener and a bullpen day, we really need all of our pieces functioning. He probably needs three or four days down to do nothing, and we aren't in a position to really afford that."

The first of what is expected to be many prospects to join the team at the end of the season arrived at Comerica Park to take his place on the roster.

Hard-throwing left-hander Taylor Guilbeau, who was one of three pitchers acquired at the MLB trade deadline from the Nationals in exchange for Roenis Elias and Hunter Strickland, had his minor-league contract selected and was added to the 40-man and active roster.

When he steps on the mound, Guilbeau, 26, will be making his big-league debut. He will be the 62nd player and the 40th pitcher used by the Mariners this season. The Rangers hold the record for players used, 64 in 2014. The 2017 Mariners also used 40 pitchers.

"That's what it is now?" Servais said. "Forty pitchers. We aren't done. We'll have some more in September. It's the year of opportunity."

Guilbeau has been pitching for Class AAA Tacoma since being acquired. He's got a 1.80 earned-run average with five strikeouts and two walks in five innings pitched over five appearances. He's rated as the No. 22 prospect in the Mariners organization by MLB Pipeline.

He had an interesting Wednesday in terms of travel. He flew with Class AAA Tacoma out of New Orleans through Denver and into Seattle-Tacoma International Airport. When the team landed, manager Daren Brown approached him in the airport.

"He asked me if I slept on the flight," Guilbeau said. "I told him, 'Nah, I can't really sleep good on flights.' And he said, 'Well, maybe you'll sleep better on this next one, 'cause you are going to the big leagues.'"

Guilbeau took the red-eye out of Sea-Tac at 9:40 p.m. and arrived in Detroit at 5 a.m. Thursday morning.

"I got about two hours of sleep in the clubhouse and I'm ready to go," he said. "I've been dreaming about this my whole life."

Brennan pitched in three games after returning from the injured list Aug. 6. He missed 42 games already this season with a shoulder strain. He exited his appearance Tuesday night after throwing just two pitches and feeling fatigue in his shoulder. Brennan had worked out earlier in the day, threw before the game and then threw 30 pitches in the bullpen while waiting to come into the game

"They need as many fresh arms as possible, and since I need a couple of days, it's just bad timing for me," he said.

Brennan thinks he should be ready to return when the 10-day minimum is reached. This isn't like the shoulder strain that kept him out over a month.

"This is nowhere near as bad," he said. "The first time I really had no idea what it was because it was kind of stemming from my back to my lat to my shoulder. My whole body was kind of fatigued on the right side in general whereas right now I have it isolated. Today it feels way better than it felt two days ago."

Also

--Making his third rehab start, and his second for short-season Everett, Felix Hernandez pitched four shutout innings, allowing one hit and striking out eight batters Wednesday night at Funko Field.

"Pretty good," Servais said of the report. "He threw a lot of strikes. His arm felt great coming out of the game. Definitely the most positive report we've gotten about Felix so far, which is awesome."

Servais said Hernandez still needs to "face stiffer competition" before being re-inserted into the starting rotation. He is expected to start either Monday or Tuesday night at Cheney Stadium.

--Mitch Haniger and Braden Bishop -- also on rehab stints -- both played for High-A Modesto Wednesday night. It was Haniger's second rehab game. He started in right field and had three plate appearances, going 0 for 2 with a walk. Bishop played in his first game, starting at designated hitter and going 0 for 4.

"Everything came out OK," Servais said. "Those guys haven't played in so long it's going to take some time to get their timing and their understanding of where they are at with their strike-zone judgment."

Haniger is expected to join Tacoma this weekend while Bishop will remain with Modesto.

--The Mariners have promoted talented young outfield prospect Julio Rodriguez to High-A Modesto for the final weeks of the 2019 season. After missing six weeks with a broken hand, Rodriguez, 18, played in a total of 67 games for Low-A West Virginia, slashing .293/.359/.490 (batting average, on-base percentage and slugging percentage) with 20 doubles, a triple, a 10 homers and 50 RBI.

Rodriguez earned the promotion, but it may also have a secondary purpose. Sources indicated that Rodriguez, along with top outfield prospect Jarred Kelenic, will participate in the prestigious Arizona Fall League for the top prospects in baseball. Having Rodriguez play in the elevated competition of the Cal League will offer good preparation for the AFL, where he likely will be the youngest player to participate.

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