Looking to maintain his success versus Colorado, the right-hander will try to help the visiting Nationals improve to 5-0 this season against a Rockies team trying to avoid a seventh straight defeat Tuesday night.Zimmermann (6-5, 3.03 ERA) allowed seven runs in 50 innings while going 3-2 during a seven-start stretch prior to July 11, when he gave up four runs in 3 1/3 innings before departing a 6-2 loss at Philadelphia because of a biceps strain.Though the injury forced Zimmermann to miss last week's All-Star game, he didn't encounter any problems during a weekend bullpen session."He is good to go," manager Matt Williams told MLB's official website. "We will not go in with any (pitch) limit on him. He can go as normal as long as he feels good."Zimmermann allowed two runs in six innings of a 7-3 win June 30 to improve to 5-0 with a 1.64 ERA in seven starts versus Colorado (40-59). He's 2-0 with a 2.70 ERA in three outings at Coors Field.He won't have to face Justin Morneau, who was placed on the disabled list Monday with a neck strain.It's uncertain if star Rockies shortstop Troy Tulowitzki will miss a third consecutive contest with a thigh injury. Tulowitzki is hitting a major league-high .340 with 21 home runs and 52 RBIs, but he and the team plan to take the cautious approach."Numerous times in my career I've played through things like this and gotten myself in trouble," he said. "So it's time to be smart. And when I get back out there, that I'm able to go 100 percent."Colorado also placed reliever Boone Logan on the DL with diverticulitis.Teammate Carlos Gonzalez appeared to jam both wrists sliding into third base in the sixth inning of Monday's 7-2 loss to Washington (54-43), but remained in the game.Gonzalez is batting .214 (6 for 28) in seven games since missing more than a month with a finger injury for the Rockies, who have dropped 24 of 30 since winning a season-high five in a row."I don't know what else can happen this year," Gonzalez said.All-Star Charlie Blackmon, however, went 1 for 5 after sitting out Sunday with a sore ankle. He's batting .467 (14 for 30) in his last seven games and is 1 for 3 versus Zimmermann.Ian Desmond belted a two-run homer for one of his five hits Monday for the NL East-leading Nationals, who have won three straight and 13 of 18."Anytime we win, it's a great day," Monday's winning pitcher Doug Fister said. "We want to make sure we get that winning feeling."Desmond is hitting .385 with three home runs and 13 RBIs in his last 13 games, and .618 (21 for 34) with three homers and 12 RBIs in his last eight at Coors Field.He went 1 for 2 with a double off Yohan Flande (0-2, 7.36), who gave up three runs in 5 1/3 innings while opposing Zimmermann last month in his second career start.The left-hander followed that effort by allowing five runs and nine hits in 4 1/3 innings of an 8-2 loss to the Los Angeles Dodgers on July 6.