By Bruce Levine–

GLENDALE, Ariz. (CBS) — The final numbers for closer David Robertson are a bit deceiving from his first year with the White Sox. Robertston was tied for the most blown saves in baseball in 2015 despite his overall season being a positive for the South Siders.

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His 34 saves, 3.41 ERA, 0.93 WHIP and 12.2 strikeouts per nine innings were all quality marks, and he still converted 83 percent of his save chances.

After having replaced the great Mariano Rivera in 2014 with the Yankees, Robertson signed a four-year, $46-million deal with the White Sox before the 2015 season, as Chicago was sure it had identified the right man for the job.

Thi spring, the 30-year-old Robertson has been working on making life easier on himself with less volume in his tool box and more quality pitches. He has variations of five different pitches, including two fastballs and three breaking pitches. If you include changes of speed, the number of pitches Robertson has can vary from five to 10, which is difficult for hitters to keep track of.

When Robertson is on, he’s at the top of his profession.

“It helped at the beginning of the year last year when the weather was cold up north,” Robertson said of his strong start to 2015. “This year I am really just working on control. I am trying to work my two-seamer (sinking fastball) inside a little more. The rest is all about getting my body ready for the year. I definitely want to have a better season this time around.”

Robertson was sensational in his debut with the White Sox, registering 12 consecutive scoreless outings to start the 2015 season. Then his performance went a bit sideways with some bloops and blasts after that.

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“This game can mess with you,” Robertson said. “You have to forget about the flares that get you or else they get followed up with bigger hits. You have to remember the line drives that were hit to end a rally as well. Last year is over. I am hoping for a more positive one this season.”

How do you hit Robertson?

“I had to look for a zone to protect,” teammate Melky Cabrera said of his past experiences. “He tries to get you to move your eyes. He’s very tough.”

White Sox catcher Dioner Navarro had a different take.

“I did well sometimes looking for the breaking ball from him,” Navarro said. “You better get something you like in the first three pitches or else you are out.”

Robertson’s working on the physical side of the game for now.

“I am trying to use less pitches with better results,” Robertson said. “But since I have more pitches, it’s nice to throw variations to guys you have seen often. You have to show them something different, to get them thinking. You do that to get them off of your main pitches.”

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Bruce Levine covers the Cubs and White Sox for 670 The Score and CBSChicago.com. Follow him on Twitter @MLBBruceLevine.