Extra bases

Extra bases

James Russell is tied for first for the most appearances in the Major Leagues by a reliever, pitching in 73 games this season. On Saturday, he served up a game-winning home run to the Pirates' Marlon Byrd, and has given up four hits and two walks over three innings in his last four games.

"The ball's up," Sveum said of the lefty. "Even the out he got on [Pedro] Alvarez [on Saturday], every pitch he threw was up in the strike zone. It's a matter of keeping the ball down. He's having a real difficult time getting the ball down."

Could Russell be tired?

"For whatever reason, mechanical or tired or whatever -- he's had quite a bit of rest the last few weeks," Sveum said. "We've tried not to use him unless we're tied or teams we're playing are in the pennant race to give him a break. He has thrown a lot of pitches and innings the last couple years, but he says he feels as good as he ever has."

Russell is the fifth Cubs lefty to record multiple 70-game seasons for the team, and first since Sean Marshall did so in 2010-11.

Scott Baker will get one more start on Friday at Wrigley Field when the Cubs play the Braves, and then the right-hander will be shut down. Sveum said there has been no talk about having Baker make another start.

In two starts, Baker, coming back from Tommy John surgery in April 2012, has given up one run on five hits and one walk over 11 innings.

• The Cubs played the Pirates on Opening Day, but Chicago's roster in this four-game series has undergone several changes. Only 12 of the 25 players on the Cubs' Opening Day roster are still with the team. The 13 players no longer present have either been traded, outrighted off the 40-man roster, or granted their unconditional release.

Nate Schierholtz is the lone outfielder remaining from Opening Day, and Russell and Hector Rondon are the only remaining relievers.

Overall, 33 players have made their debut for the Cubs this season, a franchise record that tops the 30 who did so in 1902.

Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.