HOUSTON -- Mariners reliever Sam Tuivailala will require surgery on his injured Achilles tendon and is going to miss the rest of the season, manager Scott Servais said on Saturday.
The young right-hander was acquired from the Cardinals on July 27 for Minor League reliever Seth Elledge and posted a 1.69 ERA in his first five games before getting hurt Wednesday in a rundown at Texas.
"I was really excited by what we were seeing," Servais said. "I thought once he got comfortable and we had a chance to see him a little more, you start maybe adding some things to what he does and see where it can go from there. But that's going to have to be put on hold for now."
It's not certain yet whether Tuivailala will be ready for the start of Spring Training next year, but he definitely figures in the Mariners' long-term plans. The 25-year-old won't be arbitration eligible until after next season and has four more years of team control remaining.
Ramirez ready to go
The Mariners won't likely make it official until prior to Sunday's game, but Erasmo Ramirez was already with the team Saturday and preparing to take Felix Hernandez's spot on Sunday against Astros lefty Dallas Keuchel.
The 28-year-old right-hander has been sidelined since May 1 with a strained shoulder, but he started four Minor League rehab games in the past two weeks and has a 2.77 ERA with 11 hits, 16 strikeouts and two walks in 13 innings in three outings for Tacoma and one with Double-A Arkansas.
"I know he wasn't as sharp his last time out, but he's certainly started plenty of games in the big leagues and did a nice job for us last year," Servais said. "He wasn't himself early in the season with the setback in Spring Training and going from there. We'll just fire him out there, eyeball it and see how it goes."

Ramirez posted a 3.35 ERA in his final nine starts with Seattle last year after being re-acquired from the Rays in late July for Steve Cishek and was ticketed to be the Mariners' No. 4 starter until getting derailed by injuries in Spring Training.
"Sinker, cutter, he's got all the pitches," Servais said. "He lives at the bottom of the strike zone. When he's going right, he's pretty efficient. He can get you through six innings when he's built up and going right. I hope he has a few of those outings in him because we need him."
Worth noting
• Left-hander Roenis Elias will make another Minor League rehab outing after pitching a perfect inning in his first game with Tacoma on Thursday as he returns from a triceps strain.
• Robinson Cano went 2-for-4 and hit a grand slam for Short-Season Class A Everett on Friday in his fourth Minor League game as he prepares for his return to the Mariners next Tuesday in Oakland. Cano, serving an 80-game suspension, played first base on Friday and was slated to start at third base on Saturday for the Aqua Sox.
Cano is 7-for-15 with two home runs and six RBIs in his first four games, two with Triple-A Tacoma and two with Everett.