In the second game of the Cubs' series against the Mets at Wrigley Field on Wednesday, Chicago's Edwin Jackson will match up against New York's Daisuke Matsuzaka.
The Cubs' 2-1 walk-off win in Tuesday's series opener cooled off the Mets (28-30), who came into the game on a three-game winning streak and were 7-3 in their previous 10 games, but Chicago still has the worst record in baseball at 21-34.
"It's just a short snippet of a season," Cubs manager Rick Renteria said. "Do I expect or hope we continue to improve and get better? Absolutely. Is it something we've talked about as a club? Yes, we have. I still try to keep my vision totally on the field and look at things we're doing well and hopefully move forward."
Jackson is 3-5 with a 4.81 ERA after losing to the National League West-leading Giants in his last start -- although he only allowed two runs on four hits in 5 1/3 innings and struck out nine.
That concluded a 1-3 May for Jackson, a record which -- like the loss against the Giants -- wasn't exactly representative of how the right-hander pitched. His ERA was almost a full run lower in May (4.30) than in April (5.24), when he went 2-2.
And that 4.30 May ERA includes a four-inning, eight-run outlier against the Padres. In Jackson's other four starts, he gave up six total runs in 25 1/3 innings.
His opponent, Matsuzaka, has been a sort of utility arm for the Mets, mostly out of the bullpen. He has one save, he's been a long man and he's started once, against Arizona on May 25. On Wednesday, he'll start again.
"He's saved us in a lot of ways," Mets manager Terry Collins said. "He's pitched in every role that we've asked him to pitch. He's pitched in the middle, he's saved a game, he's pitched in the eighth inning, he's set up, he's started. He has certainly been a real valuable guy on our staff."
The Mets played three straight extra-inning games against the Phillies in their last series, and needed a fresh arm in a tired bullpen. To make room for a callup, they sent down rookie starter Rafael Montero. That opened up a spot in the rotation, which Matsuzaka will take.
Matsuzaka is 2-0 with a 2.45 ERA in 17 appearances.
Mets: Mixing and matching atop the order
With both Eric Young Jr. and Juan Lagares on the disabled list, the Mets are searching for an everyday leadoff hitter. The past two nights, it has been center fielder Matt den Dekker, who responded Tuesday with a leadoff single, stolen base and run scored in the first inning.
Manager Terry Collins' main issue is that none of his leadoff candidates -- den Dekker, Chris Young, Ruben Tejada and Bobby Abreu -- are playing every day. Collins said he is not currently considering Abreu for the job because he values his run-producing potential lower in the batting order.
Until either Eric Young or Lagares return from the DL, Collins will continue to mix and match his leadoff hitters based on matchups, with den Dekker perhaps holding an advantage over others if he continues to produce.
"He's going to play some games," Collins said. "I'm not sure how many."
Cubs: Castillo heads to DL
Welington Castillo said he felt something "pop" during his first at-bat Sunday. The pain didn't go away, and on Tuesday, the Cubs placed their regular catcher on the disabled list after an MRI revealed a strained left rib cage.
Chicago selected the contract of catcher Eli Whiteside from Triple-A Iowa, and he joined the team Tuesday.
Castillo came out of Sunday's game in Milwaukee after four innings because of soreness in his side. The Cubs had hoped that a day off on Monday would help, but he still had pain and underwent the MRI.
"I took a swing, my first swing, and I just felt something pop," Castillo said Tuesday. "I tried to keep playing, but it was getting worse and worse."
Castillo was batting .242 in 43 games with five home runs and 21 RBIs. Whiteside was a non-roster invitee this spring, and he was batting .171 in 33 games at Iowa.
"It's a situation with the rib that doesn't seem to be long term," Renteria said. "We're hopeful the inflammation surrounding it can go down. Hopefully, it's not a long stint on the DL."
• Kris Bryant, the Cubs' No. 2 prospect, was named the MLB Pipeline Hitting Prospect of the Month for May, after batting .407 with 12 homers and 34 RBIs in 29 games with the Tennessee Smokies.
• The Cubs have the fourth overall pick on Thursday in the First-Year Player Draft. Their next pick is in the second round, 45th overall.
• The Mets pick at No. 10 overall on Thursday, and then don't pick again until the third round, when they have the 84th overall pick.
David Adler is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.