With two spots in the Cubs' rotation next season already locked up by Matt Garza and Jeff Samardzija, both of whom won't pitch again this season, Chicago will be looking to bolster the rest of its rotation.
"There's, obviously, some pieces we have to put together," Cubs manager Dale Sveum said. "The more competition and the more you have, the better you'll be."
That's where Volstad will step in and try to solidify his role. The righty struggled much of the season, starting 0-9 with a 6.88 ERA before earning his first win on Aug. 26. Since then, however, he is 2-0 with a 3.64 ERA over his last three starts, despite giving up five runs on nine hits (three homers) in five innings his last time out.
As for Keuchel, he will be making his first start since logging a brief stint with Triple-A Oklahoma City, as the Astros move to a six-man rotation for the season's final stretch.
Keuchel is aiming to halt a personal seven-decision losing streak when he takes the mound on Monday. The rookie earned his first career win on June 23, when he pitched a one-run complete game against the Indians. Since then, he is 0-7 in 10 starts for the Astros.
"We want to make sure at the end of the year we have a chance to evaluate all these pitchers to see who's in line at the end of the season," Houston interim manager Tony DeFrancesco said last week.
Cubs: Barney tops Sandberg's errorless mark
Second baseman Darwin Barney broke Ryne Sandberg's National League single-season record with his 124th consecutive errorless game on Saturday, and extended the mark to 125 in Sunday's series finale against the Pirates.
Sandberg set the NL mark at 123 between June 21, 1989-May 17, 1990. The Major League-record, single-season errorless streak by a second baseman is 141 games, set by Placido Polanco in 2007 with the Tigers. Barney has enough games remaining that he could catch Polanco, and Barney's stellar defense has Sveum believing the second baseman is worthy of an NL Gold Glove Award.
"He's had such an exceptional defensive season that it stands out as possibly one of the best of all time," Sveum said. "Hopefully, that is enough to sway people."
Astros: Lowrie could return soon
Shortstop Jed Lowrie continues to progress in his rehab stint, and that's good news for an injury-riddled Astros middle infield.
Lowrie, who has been sidelined with a nerve injury in his right leg since July 15, went 0-for-4 as a designated hitter for Class A Advanced Lancaster on Saturday, but drove in a pair of runs and scored another.
"I know Jed flew to Lancaster [on Saturday] and got a couple at-bats and a couple RBIs, so that's encouraging," said DeFrancesco. "They won the game, so hopefully he'll be in the field [on Sunday] for four or five innings."
DeFrancesco said the plan was originally to have Lowrie play the field on Saturday. It would be his first field action since his injury.
With the Astros returning to Houston on Monday for a seven-game homestand, starting pitchers Bud Norris and Lucas Harrell will get starts at Minute Maid Park. The two starters rank Nos. 1 and 2 in the National League in home ERA this season at 1.90 and 2.06, respectively.