Wilhelmsen was immediately active on the Mariners' roster. Despite his struggles in Texas, general manager Jerry Dipoto said the club believes Wilhelmsen is "not very far removed from being a very good Major League pitcher."
"Of all the offseason moves we made, trading Tom was one of the most difficult," Dipoto said. "He was a very stable and controllable bullpen guy. He's comfortable here and we're glad to get him back."
Wilhelmsen allowed five or more runs in three of his relief appearances with the Rangers, but he is already putting his struggles in the rearview mirror.
"I don't think anything really [worked]," he said of his time in Texas. "You can look at it. It wasn't pretty. No, it was really hard to deal with. It was without a doubt the hardest stretch of my career. I could sit here and wonder why, but the best part about this move is that's over and done with, and there's no sense in looking back at it."
To make room for Wilhelmsen, Seattle optioned right-handed reliever Jonathan Aro to Triple-A Tacoma and transferred Charlie Furbush to the 60-day disabled list.
Wilhelmsen walked around the visitors' clubhouse before Wednesday's game against the Tigers with a smile on his face, just happy to be back in the place he calls home.
"No doubt, I was a little heartbroken when I got sent away, but that's the nature of the game and you move on from that," he said. "Unfortunately, it didn't work out for me, and ultimately, I want to be happy. There's nothing better than that, and I was mighty happy here in Seattle, and I'm even happier to be back."
Wilhelmsen was traded in November as part of a deal that sent outfielder James Jones and infielder Patrick Kivlehan to Texas in exchange for center fielder Leonys Martin and reliever Anthony Bass.
Wilhelmsen last pitched for the Rangers on June 13. Mariners manager Scott Servais had a chance to meet with him Wednesday morning and is happy to have the righty back in Seattle.
"Our bullpen should be in pretty good shape here tonight, so hopefully we won't need him tonight," Servais said. "You never know what happens after that, but hopefully we'll get a chance to get him off the mound."
Wilhelmsen said he was able to get some conditioning and light throwing in during his week and a half away from the game. He said his arm and body feel good and he is ready to go.