JUPITER, Fla. -- Whether it is Opening Day, or the game after, Jose Urena's focus remains the same -- be prepared for anything.
Marlins manager Don Mattingly has already said either Urena or Dan Straily will start the March 29 opener against the Cubs, at Marlins Park. Whoever isn't starting will get the second game.
"We talk all time," Urena said of Straily. "We are focusing on doing the best we can. It doesn't matter who goes out there. Any time we go out there, we're trying to do the best we can."
Exactly three weeks before Opening Day, Urena threw three innings, giving up one run on Thursday in the Marlins' 5-4 loss to the Cardinals at Roger Dean Chevrolet Stadium.
"Jose threw good," Mattingly said. "We got his pitch count up there a little bit. He threw some more in the bullpen. He's kind of building towards 75-80 [pitches]. He's kind of getting to where he needs to be, building that pitch count up."
Urena, whose fastball topped at 97 mph on Thursday, surrendered two hits, walked two and struck out two. In seven Grapefruit League innings, he has an ERA of 1.29, and for the most part has looked impressive.
Straily, who starts on Friday against the Red Sox in Jupiter, hasn't allowed a run in five innings.
Urena is in a completely different situation from last Spring Training, when he was out of options and didn't know if he would even be on the team. Not only did he make it, he paced the club in wins, going 14-7 with a 3.82 ERA.
"The thing for me, personally, you've got to push yourself all the time," Urena said. "You've got to do the best you can. If you don't make it, you can still feel good about yourself, saying, 'I did the best I could, but didn't make it.'
"It's about you first. How you can prepare. What you can do. If you think, 'Oh, I'm out of options,' maybe you try to push yourself harder. Maybe you don't do what you have to do, because you put pressure on yourself."
Position battle
Braxton Lee, rated by MLB Pipeline as the Marlins' 17th-ranked prospect, remains firmly in the mix for a starting-outfield and Opening Day roster spot.
"I think he deserves consideration," Mattingly said.
The left-handed-hitting speedster had two hits and a walk on Thursday.
"There's still at-bats for these guys," Mattingly said. "I like what I've seen out of Brax. He can play all three outfield spots. He's got speed. He will play a short game, where he will bunt. And he can bunt."
Lee, who was the co-batting champion in the Double-A Southern League last year, is in the mix to play either center or right field. The two locks for the outfield are Cameron Maybin and Derek Dietrich. Lee, Lewis Brinson and Magneuris Sierra are also competing to play center.
"We haven't set a club," Mattingly said. "We haven't set a roster yet. We talk about competition. We're still in the middle of it."

Injury update
Isan Diaz, Miami's No. 8-ranked prospect according to MLB Pipeline, was in the lineup on Thursday against the Cardinals. There were some concerns for the second-base prospect because in Wednesday's 7-6 win at the Astros, he was shaken up in a collision with teammate Isaac Galloway. Diaz bruised his left knee, but it didn't cause him to miss a game.
Up next
The Marlins on Friday face the Red Sox at 1:05 p.m. ET at Roger Dean Chevrolet Stadium in a game airing live via an exclusive Marlins.com audio webcast. The pitching matchup will feature Straily vs. Chris Sale. Brinson, the Marlins' top prospect, is scheduled to lead off and play center field. Dietrich, Starlin Castro, Justin Bour, J.T. Realmuto and Brian Anderson are among the regulars set to play.