Nationals manager Davey Johnson thinks we still haven't seen the best of Stephen Strasburg. That must be an alarming thought for the rest of the National League.

Strasburg takes his shot at a seventh straight victory this evening as Washington plays the first of four straight against the Colorado Rockies.

The right-hander's current winning streak has improved his season record to 9-1 with a 2.46 earned run average through 14 starts as he hasn't lost since May 15. Strasburg logged seven innings of work for the second time over his run in a win versus the Rays on Wednesday, scattering two runs on five hits and a pair of walks while striking out 10.

Strasburg also threw 111 pitches, his second-highest total of the season.

"He's a true No. 1 and he's still learning," remarked Johnson about Strasburg. "I think the best is yet to come with him."

The 23-year-old has certainly flashed some of his best stuff on the road, where he is 5-0 with a 2.30 ERA in seven starts this year. He faces the Rockies for the first time.

While Strasburg continues to get his feet wet in the majors, Rockies starter Jeff Francis will make the 184th start of his career and third this season with the Rockies.

After pitching last season with the Royals, the 31-year-old southpaw has returned to the organization that selected him ninth overall in 2002.

Francis, who spent the first six seasons of his career with the Rockies, is 0-1 with an 8.56 ERA through three starts, the bulk of that coming in his season debut on June 9 versus the Angels, who tagged him for eight runs over 3 1/3 frames.

Francis turned in a solid outing on Thursday in Philadelphia, though it began by him allowing a solo homer in the first. That ended up being the only run he gave up in his five frames of work as he logged a no-decision. Things could have been worse after an error in the second put two runners on, but Francis retired the next two batters to end the frame.

"He did a terrific job in picking us up after the defensive miscue," Rockies manager Jim Tracy said of Francis.

The veteran is 1-1 with a 4.91 ERA in five career starts against the Nationals.

Both the Rockies and Nats come into this series struggling. Colorado has lost six of eight to fall 17 games under .500 at 27-44, while Washington has dropped six of nine.

The Nationals were edged 2-1 by the Orioles in Sunday's rubber match of a three-game series as reliever Sean Burnett gave up a go-ahead, two-run homer to Baltimore's Matt Wieters in the eighth inning.

"We play a lot of close games and our bullpen expects to get the job done," Burnett said. "We've done a great job most of the year but today I let one slip away."

Ryan Zimmerman, who earlier on Sunday received a cortisone shot in his right shoulder, knocked in the only Washington run with an RBI single and Bryce Harper added a pair of hits in defeat for the Nats, who still own a 3 1/2-game lead for first place in the National League East.

The Rockies also dropped a rubber match on Sunday, falling 4-2 to the Rangers.

Marco Scutaro ripped an RBI single and Carlos Gonzalez chipped in with an RBI on a sacrifice fly for the Rockies, but starter Alex White yielded four runs on six hits with three strikeouts and four walks in just 2 2/3 innings to absorb the loss.

The Rockies have won seven of their past 10 versus the Nationals.