Cubs 6, Mariners 3

Not long after learning he had locked up the fourth spot in Chicago's rotation, Randy Wells went out and showed why the Cubs have confidence in him.

Wells pitched Chicago to a 6-3 victory over a Seattle Mariners split squad Friday, striking out eight in 5 2-3 solid innings. He gave up five hits and three runs as the Cubs won their third straight.

Even though Wells was all but a lock to be the team's No. 4 starter, manager Mike Quade waited until Friday morning to make the announcement.

Wells was happy with the way he pitched and even happier to know his job was secure after a sound spring.

''I pretty much accomplished what I wanted to,'' he said. ''I put a couple things on my goal list, and one was to have a strong spring and show the team that last year was a fluke, a down year, and that I'm a better pitcher than I showed last year.''

The 28-year-old Wells enjoyed a strong rookie season in 2009, going 12-10 with a 3.05 ERA. Last year was a struggle at times, and he dropped off to 8-14 with a 4.26 ERA. He said that concentration on the mound was the major issue holding him back.

''I was working on focus, putting baseball as a huge priority and coming to the field every day wanting to learn, eager to learn,'' he said.

This spring, Wells is 1-1 with a 2.10 ERA.

''He's had a marvelous spring,'' said Quade, who called Wells in before his start to give him the good news. ''I've gotten wrapped up in so many decisions that I finally had to go to him today and say, 'Hey, by the way, make sure you know how to get to Chicago.'''

Starlin Castro hit a three-run double in the seventh inning to rally Chicago from a 3-2 deficit.

The Mariners scored twice against Wells in the first inning on an RBI single by Jack Cust and a run-scoring double by Justin Smoak. Seattle made it 3-0 in the fourth on an RBI single by Adam Moore.

Seattle left-hander Aaron Laffey, competing for a spot in the bullpen, worked four innings, giving up three hits and one run. He walked one and struck out four.

Laffey was acquired from Cleveland in a March 2 trade.

The win went to Sean Marshall, who worked a scoreless seventh. Marcos Mateo earned his first save.

Cesar Jimenez took the loss.

Blake DeWitt hit his first homer of the spring for the Cubs.

Smoak finished with a pair of doubles.

NOTES: RHP Braden Looper retired after failing to make the Cubs as a non-roster invitee. The 36-year-old Looper sat out last season after going 14-7 with a 5.22 ERA for Milwaukee in 2009. He chose not to pitch last season because he said he did not get a contract to his liking. ''After taking a year off, he came in and gave it a good shot,'' Cubs general manager Jim Hendry said. ''We just felt in the end he wasn't going to be able to break with the 12 (pitchers). He certainly had an outstanding career. We felt it was a good, sound idea. I'm glad we did it.'' ... Cubs 2B Jeff Baker left in the fourth inning with a tight left hamstring. He is day-to-day.