MESA, Ariz. -- Jeff Samardzija will start the Cubs' Cactus League opener, but manager Rick Renteria isn't ready to name his Opening Day starter just yet.
Samardzija, who did start Opening Day 2013, tested the mound at new Cubs Park on Monday with a brief workout. On Thursday, he'll open the Cactus League season and Cubs Park's first year against the D-backs.
"So many things can happen over the course of the spring, I'm not going to lock myself into trying to divulge something I can't determine what it will be in the end," Renteria said when asked who would start March 31 when the Cubs open the season against the Pirates.
In Cactus League action, lefty Chris Rusin will start Friday against the Angels in Tempe. On Saturday, the Cubs have a day-night doubleheader. Travis Wood will go in the first game in Mesa against the Giants, and Edwin Jackson will start the night game against the D-backs in Scottsdale.
Jason Hammel, who signed a one-year, $6 million contract with the Cubs earlier this month, will start Sunday against the Royals.
Whiteside adjusting to new collision rule
MESA, Ariz. -- Cubs catcher Eli Whiteside was in the Giants' dugout on May 25, 2011, when Buster Posey sustained a season-ending leg injury in a collision at home plate, and remembers the pain everyone felt after the freak accident.
On Monday, Major League Baseball and the Players Association took a step to avoid a repeat of what happened to Posey.
MLB and the MLBPA added Rule 7.13, which covers collisions at home plate, on an experimental basis for the 2014 season. The goal of the rule is to "prohibit the most egregious collisions at home plate."
The experimental rule states that "a runner attempting to score may not deviate from his direct pathway to the plate in order to initiate contact with the catcher (or other player covering home plate). If, in the judgment of the umpire, a runner attempting to score initiates contact with the catcher (or other player covering home plate) in such a manner, the umpire shall declare the runner out (even if the player covering home plate loses possession of the ball)."
The rule also states that "unless the catcher is in possession of the ball, the catcher cannot block the pathway of the runner as he is attempting to score. If, in the judgment of the umpire, the catcher, without possession of the ball, blocks the pathway of the runner, the umpire shall call or signal the runner safe."
Whiteside and the other Cubs catchers in camp have been working on different tags and positioning with coach Mike Borzello, but were not sure exactly what was allowed.
"We've kind of tried to work on it out there and didn't know what to do," Whiteside said. "It's kind of a gray area. It's tough to hold your ground and play the ball at the same time, especially with the ball coming from different angles in the outfield. We'll just have to see how the rule is written and see how it plays out to figure out how we're going to work on that play and go about trying to make that play."
Cubs manager Rick Renteria joined other Cactus League managers on Monday at a meeting with MLB officials to go over the rule change.
The rule states that "in determining whether a runner deviated from his pathway in order to initiate a collision, the umpire will consider whether the runner made an effort to touch the plate, and whether he lowered his shoulders or pushed through with his hands, elbows or arms when veering toward the catcher."
The new rule does not mandate that the runner always slide or that the catcher can never block the plate. However, runners who slide, and catchers who provide the runner with a lane to reach the plate, will never be found to be in violation of the new rule.
Instant replay will be available to review potential violations of the new rule.
"We've messed around with it a little bit," Whiteside said about positioning. "Some part of the rule will be up to the umpire's discretion. We'll see what we get and go from there."
Plus, catchers need to know what constitutes blocking the plate.
"You've got to make a play on the ball because you don't want that guy to advance, even if it is a bad throw and there's no play at the plate, you've got to play the ball and keep it in front of you so the guy doesn't advance on the throw," said Whiteside, who had yet to see the rule specifics.
After seeing Posey seriously injured, did Whiteside feel the rules needed to be changed?
"You don't ever want to see anybody get hurt," Whiteside said. "[Collisions at home have] been around in the game for a long time. It's a tough call either way. That's what they're trying to do is protect the players, and you always want to protect the players. It's kind of a tough issue."
One of things Whiteside remembers from the day Posey was hurt is how he kept seeing replays of the collision.
"It was tough for everybody, tough for our team," he said. "It is part of the game and people get hurt all the time. Hopefully, something like that doesn't happen again."
Renteria impressed with new Cubs Park
MESA, Ariz. -- There were a few problems figuring out how to get from the Cubs' complex to the field, but so far, the team's new spring stadium, Cubs Park, is passing all the tests.
On Monday, some of the Cubs, including Anthony Rizzo, Darwin Barney and Starlin Castro, had a chance to take batting practice at the new ballpark, which is a short golf cart ride from the Spring Training facility. Pitchers Jeff Samardzija and Travis Wood tested the mound in an early session. The only minor glitch was figuring out which door to use to gain access.
"It's a beautiful facility," manager Rick Renteria said. "Obviously, we came and saw it earlier, but to have them go out there and hit, we'll allow them to get a feel for the field."
What did Renteria like?
"Everything," he said. "It's brand new, [there's] expansive seating -- it's incredible. For a Spring Training facility, that's a big league ballpark."
The Cubs will play a six-inning intrasquad game on Wednesday at Cubs Park starting at 2 p.m. CT. Eric Jokisch and Kyle Hendricks will start.
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.