Cobb showed marked improvement over his first outing of the spring when he allowed two runs on four hits in two innings against the Red Sox.
"Felt good," said Cobb of his outing. "Did my bullpen, worked on a few things from my last outing. ... Carried it out to the game and I felt pretty sharp."
Wei-Yin Chen, who is projected as the Orioles' No. 2 starter, made his first appearance of the spring. The left-hander allowed no runs in two innings, throwing 23 pitches of which 17 went for strikes.
"I think my command and breaking ball control is getting better and better this year," Chen said through interpret Tim Lin.
Fernando Rodney, who will soon be leaving the Rays to play for the Dominican Republic in the World Baseball Classic, pitched a scoreless inning, facing just three hitters and striking out one.
In the fourth, new Rays shortstop Yunel Escobar hit his first home run of the spring when he drove the first pitch he saw from Brian Matusz into the bullpen in right with a man aboard. Ryan Roberts followed with a solo homer, his second of the spring, to put the Rays up 3-0.
Sean Rodriguez added a solo home run in the fifth to put the Rays up 4-0.
Up next: The Orioles will host the Phillies Sunday afternoon at Ed Smith Stadium, with right-hander Chris Tillman making his second spring start. Tillman will be opposed by Kyle Kendrick, with Miguel Gonzalez scheduled to make his first spring outing after Tillman. Dylan Bundy, Todd Redmon and Adam Russell are also slated to pitch for Baltimore, with first pitch set for 1:05 p.m. ET.
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.