If not for the homer -- the third of the spring for Morneau, the defending National League batting champ -- Walker would have finished with the best spring ERA (minimum 20 innings pitched) in Mariners history. Matt Young's 0.44 mark in 1983 remains the best.
At any rate, Walker, who fanned two on Saturday, finished with 26 strikeouts against 10 hits and five walks in 27 innings. He will pitch at the back of the Mariners' rotation.
"I thought it was good," said Walker, who is on an Opening Day roster for the first time in his career. "I really attacked the zone. I think that's going to help me a lot, if I get ahead with all my pitches -- offspeed and fastball, too. I felt like I threw my offspeed pitches for strikes a lot. I have a lot of confidence from the spring, going into the season."
Rockies starter Eddie Butler gave up six hits and five runs in 2 1/3 innings. One of the hits was Logan Morrison's second spring homer, a two-run shot in the second on a fastball he didn't get far enough inside. Butler also balked in a run. However, the Rockies' No. 2 prospect is in line to start Wednesday against the Brewers in the third game of the regular season.
"A couple of pitches today changed the outing; they were just up and in the middle," Butler said.
Up next: Felix Hernandez will make his eighth Opening Day start when the Mariners take on the Angels on Monday at 1:10 p.m. PT at Safeco Field.
Thomas Harding is a reporter for MLB.com. Read his blog, Hardball in the Rockies, follow him on Twitter @harding_at_mlb, and like his Facebook page, Thomas Harding and Friends at www.Rockies.com. This story was not subject to the approval of Major League Baseball or its clubs.