PHILADELPHIA -- Welington Castillo, who has been on the disabled list since June 2, did some rehab work on Wednesday as he comes back from left rib cage inflammation.
The catcher took 25-30 dry swings and 15-20 swings off the tee.
"Doing better," manager Rick Renteria said. "Took some dry swings, some tee work, some frontside with no complaints. Did some conditioning with no complaints. He's coming along."
Before being sidelined, Castillo was batting .242 with five home runs and 21 RBIs in 43 games.
John Baker has received the bulk of the playing time at catcher in Castillo's absence.
Bonifacio hits DL, awaits MRI results on rib cage
PHILADELPHIA -- Emilio Bonifacio was placed on the 15-day disabled list on Friday with rib cage inflammation after injuring himself during Thursday night's game against the Pirates.
On the second pitch of the game, Bonifacio grounded out to short, but he never left the batter's box. As he swung, he fell to the ground, grimacing in pain. Head athletic trainer PJ Mainville had to support Bonifacio as he limped off the field.
Bonifacio had an MRI on Friday.
"We'll wait until they give us the MRI to actually find out what it is," Cubs manager Rick Renteria said.
In the meantime, the Cubs have activated Ryan Sweeney from the 15-day disabled list. Sweeney, who had been sidelined since May 3 with a right hamstring strain, got the start in center field Friday night and was put in the No. 2 spot in the order.
Sweeney, Justin Ruggiano and Junior Lake will all get time in center field with Bonifacio on the DL.
"I'm going to keep using Sweeney and Ruggiano or Lake or any number of those three guys, because they've all done it," Renteria said. "I think as we continue to move forward, we'll just continue to do what we actually have done in the recent past here. Try and kind of match up and see what we can do with the lineup."
Bonifacio's absence also creates a void atop the Cubs' lineup, as the speedy center fielder was Chicago's everyday leadoff hitter. Renteria plans on using Chris Coghlan, Lake or Sweeney to get things started from that spot.
"Of the guys that are here, [Coghlan] has actually led off before in Miami. And we have led off [Lake] in the past," Renteria said. "So we're just going to try to mix and match and see where we go with that."
Renteria said he would consider moving up Luis Valbuena to leadoff, but for the time being, he prefers keeping him in the fifth spot in the order.
"Is it tempting? Yes. But I think that the three-, four-, five-slot there for us is working pretty well," Renteria said. "Doesn't mean that we wouldn't possibly go there somewhere down the road, but right now, I think with [Starlin] Castro protecting [Valbuena] and [Valbuena] protecting Castro ... [Valbuena] has a way of putting together really good at-bats. And it'd be nice to continue to have him there, especially with runners on base."
Cubs' top pick Schwarber homers in pro debut
Just eight days after the Cubs made him the fourth overall pick in the 2014 First-Year Player Draft, catcher Kyle Schwarber hit his first professional home run to power short-season Boise to a 4-2 victory against Tri-City on Friday.
With the Hawks trailing, 2-1, in the seventh inning, Schwarber came to the plate with two on and two out. Facing right-hander Marc Magliaro, he got ahead in the count 3-0 before driving a towering fly ball out to right field.
Right-hander David Garner pitched two scoreless innings to secure the Opening Day victory for the Hawks.
Schwarber finished the night 3-for-4 with two runs and three RBIs. He started the game at catcher and made a throwing error in the first inning.
Schwarber began the year playing for Indiana University. He hit .358 with 14 home runs and a .659 slugging percentage and helped lead the Hoosiers to the Big Ten championship. He was the first position player selected and became the highest drafted player in school history when the Cubs took him last Thursday.
Erik Bacharach is an associate reporter for MLB.com. Teddy Cahill is a reporter for MLB.com. Follow him on Twitter at @tedcahill. This story was not subject to the approval of Major League Baseball or its clubs.