Coming off a World Series title, Boston wanted to bring Lackey along slowly along with Jon Lester, who made his first appearance Monday.
Lackey missed the 2012 season while recuperating from elbow ligament-replacement surgery and pitched 215 1/3 innings during the regular season and postseason last year. He allowed four hits against the Marlins, struck out two and walked none.
"It felt all right," he said. "It was a good place to start. I pretty much threw all fastballs the first two innings, tried to work on a few other things that third inning, got a little tired, probably be a little sore tomorrow. It's just a little step up in intensity, but good place to start."
Red Sox bench coach Torey Lovullo acted as manager; John Farrell was in Sarasota with the other split squad that played the Baltimore Orioles. Lovullo was satisfied with Lackey's outing.
"He made some pitches in his final inning that ran his pitch count up," Lovullo said. "But overall, for the first time he stepped on the mound, his fastball was downhill. He was locating it. I think the idea for him was to get his legs under him and make those types of pitches."
Marlins manager Mike Redmond was happy with Flynn's performance.
"Definitely his best outing of the spring," Redmond said. "His tempo was good. He had some nice downward tilt to his fastball and got some relatively easy outs. That's the best I've seen him, probably including last year during the season. He had command of his off-speed pitches and pounded the strike zone, which is nice to see."
Infielder Jeff Baker left Monday's game in the second inning with a strained left quadriceps and is day to day.
Infielder Rafael Furcal strained his left hamstring in Monday's game and is day to day.
Left-hander Craig Breslow, who is being brought along slowly after an increased workload last season, threw from a mound in a bullpen session Tuesday for the first time this spring training.
FOR THE RECORD:
"It felt good," Jensen said. "I came in the game, saw one pitch and closed it out. I was looking for a pitch to drive and I jumped on it early. I was hoping I got under it enough to get it over."
Center fielder Grady Sizemore, attempting to come back after more than two years of injuries, played Tuesday for the second consecutive day. He hit leadoff for the Red Sox, went 0 for 2 and played four innings in the field. It was the first time he has played on consecutive days since Sept. 19-20, 2011, with the Cleveland Indians.
"It's part of his progression," Lovullo said. "He gave us exactly what we thought, three, four innings out on defense, on back to back days, got a couple of at-bats and didn't take any steps backward."
THIS AND THAT:
The Red Sox had their public address announcer identify each pitch and the pitch count after every pitch in the game. It was an idea the Red Sox had considered implementing last year during spring training, but decided to wait.
"It's had some spirited debate," Red Sox executive vice president Charles Steinberg said. "I think we're not shy about being experimental or bold or innovative. This is not quite as dramatic as Charlie Finley's orange baseballs but one thing we all agree on: spring training is the time you would try it if you're going to try it."
If the new twist is deemed a success, it would be included in regular season games at Fenway Park.
"That's a bad idea," Lackey said. "Whoever did that hasn't been between the lines. ... For me it's not that big a deal because I'm not that worried about throwing strikes," he said. "But I could foresee that situation for somebody that's struggling throwing strikes. You're just pretty much beating the guy over the head. He realizes it was a ball; he doesn't want to hear it again."
Right-hander Nathan Eovaldi threw in a simulated game Tuesday at the Marlins' complex. He is scheduled to start Saturday against the Yankees in Panama.