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06/20/10 7:18 PM ET

Inconsistency plaguing both Cubs and Mariners

It's safe to say that the Cubs and Mariners haven't exactly lived up to expectations this season.

After all, both clubs were expected to compete for titles in their respective divisions but have been disappointments to this point, as the Cubs are 31-38 and the Mariners are 28-41.

It's not the way either team envisioned its season, and both are baffled by their struggles as they match up in a three-game Interleague series at Safeco Field that begins on Tuesday.

The Cubs have been up and down all season and have yet to string together a winning streak of more than four games, and their inconsistency has been a cause for concern.

"We're not consistent," right fielder Alfonso Soriano said. "We play one game good, the next day we play rookie ball, like we've never played before."

It's also frustrated manager Lou Piniella, who said that the team's struggles haven't come because of a lack of effort.

"Everybody's trying," Piniella said. "I've never complained about lack of effort, not one time in the four years I've been here. But to win, you've got to make plays, you've got to hit with men in scoring position. Those are the things you need to do, period."

The Mariners, meanwhile, have begun to turn it around recently and enter the series having won four straight games.

They'll turn to left-hander Jason Vargas in the series opener. He's been a pleasant surprise this season, with a 5-2 record and 2.88 ERA. He's also coming off a solid outing against the Cardinals on Wednesday, when he allowed just one run over 7 1/3 innings.

He's certainly impressed manager Don Wakamatsu.

"He is an aggressive-style pitcher, and that sets up his changeup," Wakamatsu said. "He's a guy who never gives in, competes and can field his position. He's confident and mature."

The Mariners, though, will have their hands full against Cubs right-hander Ryan Dempster, who is 5-5 with a 3.67 ERA this season.

And like Vargas, Dempster is coming off an effective start, giving up two runs over 6 2/3 innings against the A's on Wednesday.

Dempster said that the key to his success is keeping his club's place in the standings out of his head while focusing on what he can control.

"The biggest thing we have to do is enjoy every game we play and not worry about where you are in the standings and those kinds of things," Dempster said. "If you take the approach of playing to 'win today's game' and going out and giving your all, you'll find yourself in a good position."

Cubs: Ramirez on the mend
Third baseman Aramis Ramirez, who is on the disabled list with a sprained left thumb, made his second rehab start on Sunday with Class A Peoria and went 1-for-3. Ramirez, who has been on the DL since June 8, was batting .168 with five homers and 22 RBIs in 47 games with the Cubs. "He basically will let us know how he feels [on Monday]," Piniella said.

Mariners: Wilsons sharing shortstop duty
Shortstop Jack Wilson was activated from the DL on Sunday but was held out of the starting lineup in favor of Josh Wilson, who is batting .289 this season. Wakamatsu will decide who starts at shortstop on a game-by-game basis. "It's obviously a tough decision to be made," he said. "I think what we'll look at is the matchups and how [Jack's] legs will respond to playing. Those are the things we have to find out, but we plan on getting him in there."

Worth noting
WGN Radio analyst and Cubs legend Ron Santo will skip the trip to his hometown and miss the Cubs' upcoming Interleague series against the Mariners. Santo, a diabetic who had both legs amputated below the knee because of complications from the disease, is reducing his travel schedule this season because of pain in his left leg. ... Mariners right-hander Ian Snell cleared waivers and accepted his assignment to Triple-A Tacoma after being designated for assignment earlier in the week.

This story was not subject to the approval of Major League Baseball or its clubs.