Francis, 32, started the home opener. He went 2-3 with a 6.00 ERA over 36 innings before going on the DL with a left groin strain. Francis made one rehab start for Triple-A Colorado Springs on June 6, allowing three earned runs on six hits in four innings.
His 63 career wins and 1,031 2/3 innings pitched with the Rockies both rank as the second most in franchise history, trailing Aaron Cook in those categories.
Chatwood, 23, came up from Triple-A when Francis went on the DL. Chatwood has pitched well in two stints with the Rockies this season, establishing a 3-1 record and a 2.14 ERA in six starts spanning 33 2/3 innings. He experienced triceps tightness in his last start on Monday, and the Rockies hope he can return to the rotation next week after missing only one start.
"That's the plan, so we'll see what happens," Chatwood said. "I got another bullpen on Tuesday."
Chatwood threw 22 pitches on Saturday, and said he felt "much better."
Though the rotation will go through some juggling, the net result is that Francis returns to his spot, and Chatwood stays with the Rockies in Garland's spot.
Garland 33, was signed late in Spring Training after spending most of the spring with the Mariners. He made the Rockies Opening Day roster as the fifth starter, and established a 4-6 record and a 5.82 ERA in 12 starts over 68 innings for Colorado.
"These decisions are never easy," Weiss said of the Garland move. "It's not like these are no-brainers. That was a move we felt we needed to make right now with Jon. Jon did a nice job for us. He was a pro. Even yesterday, he was really professional in our meeting. It's just one of those tough decisions you've got to make over the course of a season."
The Rockies' tentative rotation will now include Francis, starting Saturday, followed by Juan Nicasio (4-2, 4.76) in Sunday's series finale, Jhoulys Chacin (3-3, 4.59) on Tuesday to open the Nationals series, Jorge De La Rosa (7-3, 3.38) on Wednesday, and Chatwood for the series finale with Washington on Thursday.