"It's basically a situation where we wanted him to go back down and regain his confidence," said Mariners acting manager Robby Thompson. "Regain pinpointing that fastball, having precise command with it like he's had in the past so his secondary stuff can work off of that."
Wilhelmsen hasn't pitched for the Mariners since the Boston blowup, but he started Tuesday afternoon's game for Tacoma, as the Mariners want to give him a chance to work on his various pitches in multi-inning situations.
Wilhelmsen threw two innings for the Rainiers, giving up three runs on three hits -- two of them homers -- while throwing 31 pitches against Iowa.
Thompson said there was no thought of converting Wilhelmsen to a starter at this point, but having him start a couple games for Tacoma helps control the situation so he can focus on his work.
"This is all about him right now," Thompson said. "It's not about trying to work him back into the closer's spot or setup guy or whatever. It's basically for Tom to get his confidence level back up, and once again, work on that fastball.
"He can go out, he can throw, and then he's done. He doesn't have to go down to the bullpen and sit around and wonder when his time is going to be. He's going to be on a set schedule, and he doesn't have to worry about any of the other stuff, other than him working on what he's down there to work on."
In his second year as closer, Wilhelmsen, 29, has posted a 4.37 ERA with 24 saves and five blown saves in 47 appearances. He saved 29 games with a 2.50 ERA last year after taking over the role from Brandon League midseason.
Wilhelmsen was out of baseball for five seasons from 2004-08 before the Mariners signed him, and he made a quick rise through the system, earning a bullpen role in '11. He was sent down to Double-A Jackson midway through that season and made 12 starts, but he returned to a relief role when he was recalled and has strictly pitched out of the bullpen since.
Rookie right-hander Danny Farquhar has successfully closed out both save situations since Wilhelmsen was taken out of the role Friday.
Capps, who turns 23 on Wednesday, is a hard-throwing right-hander who went 2-2 with a 6.37 ERA in 33 appearances for the Mariners before being optioned to Tacoma on July 11. He's been pitching well for the Rainiers, posting a 1.64 ERA in seven outings. Capps allowed six hits with four walks and nine strikeouts in 11 innings for Tacoma.
"I worked on just staying on top of the ball and trying to get a little more in line with my stride," Capps said. "I was getting pretty far across my body and I tried to straighten it up a little. I struggled a little bit with command at first, just because it was a little new. But after that I felt comfortable."
Capps will join a Mariners bullpen that has only Yoervis Medina, Brandon Maurer and Farquhar as right-handers with Wilhelmsen out of the mix.
"He's a power arm, obviously, and he's been throwing pretty well down there," Thompson said. "He's a guy that can come up and give us multiple innings. We know what Carter has done in the past. He was sent down to work on some things, also, and hopefully with his return, we'll see that, see a little advancement from him, and he'll be guy we'll be going to."