Davey Johnson would like to see his team heat up at the plate.
In the first three games of the Nationals' series against the Rockies, Washington's Nos. 3-4-5 hitters produced only eight hits in 33 at-bats. First baseman Adam LaRoche is responsible for five of those knocks.
"I think this game's 90 percent mental," Johnson said. "Anything you do in life, if you have the right mental approach to it, it's easier. I like to see good mental approaches and good, positive attitudes. That's the root of success in any business. Really, in baseball, you can talk yourself into a good hitting streak."
Colorado limited Washington to one run in Saturday's matinee, and the task doesn't get any easier for the Nats in Sunday's series finale, with Jorge De La Rosa on the mound for the Rockies. After halting a five-game skid in Saturday's 7-1 win, Colorado aims for a split of the four-game set.
De La Rosa, who yielded three runs across 5 1/3 innings against the Nationals on June 12, has compiled a 7-4 record and 3.21 ERA this season and is coming off perhaps his finest effort of the 2013 campaign.
On Monday, he held the Blue Jays scoreless on just one hit over seven innings, though he left with a no-decision in a contest the Rockies eventually dropped, 2-0. De La Rosa carried a no-hitter into the sixth inning.
De La Rosa departed after the seventh frame because of a thumb injury on his pitching hand, which led to him saying "My hand hates me" after his start. The southpaw stuck to a steady diet of offspeed pitches to be effective in Toronto.
"I threw a lot of breaking balls, and when I was behind in the count, I threw a lot of changeups," De La Rosa said. "That's why I made those quick outs."
Ross Detwiler will toe the rubber for Washington. The 27-year-old has posted a 2-5 record, despite a 3.34 ERA. He ceded three runs on six hits to the Rockies in a no-decision on June 13.
Rockies: Relievers on the mend
• Closer Rafael Betancourt and middle/long reliever Edgmer Escalona are inching closer to returning from the disabled list. Betancourt could be back by Thursday or Friday. Both pitchers are expected to face hitters in Boston next week.
"It makes it tough when you lose that closer and a guy like Escalona, who was throwing well -- he's more suited for that long role -- but there was enough power that if you needed him to throw the pitch in the seventh or the eighth, he could do that," Weiss said. "They're a couple valuable guys that we're missing right now."
Nationals: Harper sizing up rehab schedule
• Outfielder Bryce Harper said his left knee is pain-free, though he isn't sure when he'll be ready to play a rehab game. Johnson had suggested Tuesday for Harper's first appearance with Class A Potomac, but Harper said he was leaning toward Wednesday or Thursday. Johnson retorted that it isn't Harper's decision to make.
"When a player starts playing, it's really up to me, what I think they need. Not up to the player," Johnson said. "I'm always trying to do what's best for the player. But at the same time, it's my job to know when they're ready and when they're not."
• LaRoche has hit safely in 18 straight games at Nationals Park.
• The Nationals are 11-8 against left-handed starters.
• Nine of Nationals shortstop Ian Desmond's 12 home runs this season have been go-ahead blasts.
Zack Meisel is a reporter for MLB.com. Follow him on Twitter @zackmeisel. This story was not subject to the approval of Major League Baseball or its clubs.