"This time of year, honestly, you pretty much play the lineup you think is going to give you the best chance to win," Mattingly said. "Part of that may be matchups."
On Saturday, for instance, second baseman Dee Gordon was out of the starting lineup for the second straight day. Robert Andino started in his place both games.
Mattingly said that decision was based on a feeling Gordon looked tired and could use a breather. Even though the speedy second baseman didn't start in Friday's 7-6 comeback win over the Padres, he did enter the game and had three at-bats.
On Saturday, the Padres started lefty Clayton Richard, who is tough on left-handed hitters. So, the decision was made to again give Gordon some time off.
"I don't think he was very happy," Mattingly said. "But if that had been a normal game [Friday], he would have been in there today. I want to make sure he is ready to go forward."
Jeff Francoeur will spot Ichiro in right field.
Shortstop is being split between Hechavarria and Miguel Rojas.
"If there is a matchup with Miggy and Hech, you may go with that," Mattingly said. "I look at both of those guys. Hech is really, really good, but Miggy is pretty good, also, so you don't feel like you're going backwards defensively too much."
When it comes to the bullpen, Mattingly acknowledged Ramos, an All-Star for the first time, may indeed be deserving to close. But for the overall strength of the bullpen, Ramos is going to the eighth inning, with Kyle Barraclough being the primary seventh-inning right-hander.
Ramos and Barraclough may also be asked to go more than one inning.
Rodney, for instance, is viewed as a one-inning closer.
"You don't want to do it very often during the year, but when you get to a certain part of the year and you need a game, you need five outs, four outs, you're going to say, 'Here you go,' " Mattingly said. "You talk about it before you get into a game, or get into a series, you let guys know. So in their mind, they know, don't be alarmed if the call comes and it's you."
Outfielder Oswaldo Arcia, designated for assignment by the Marlins after they acquired Francoeur from the Braves, was claimed off waivers by the Padres on Saturday.