A bad back caused Phil Mickelson to go without a win last year for the first time since 2003.

“This last year and a half has not been my best,” he said. “It’s been terrible.”

But Mickelson’s back is starting to feel better, and he’s hopeful of winning the Masters this week for the fourth time in his career, obviously a much better result than last year, when he missed the cut.

Mickelson, 44, warmed up for Augusta National with two good opening rounds in the Valero Texas Open in San Antonio and three strong rounds at the Shell Houston Open, where he posted a season-high 23 birdies, tops in the field.

Call it the magic of looking forward to Magnolia Lane.

“Feels like it’s slowly getting better, and the last couple of weeks were a good couple of weeks because I got my aggressive play back,” he said. “I got a lot of birdies again. That what I kind of needed.”

The tightness that Mickelson felt in his back last year led to a slower swing speed, which can affect the timing of club striking the ball and lead to all sorts of bad things. In 21 events he posted one top-10 finish. He had never had fewer than four since joining the PGA Tour in 1992.

Mickelson worked hard to regain the lost speed by, duh, swinging faster. To do that he said he had to strengthen his muscles to handle the stress and then train them to move faster.

He did that through a series of exercises where he would swing a driver that was 20 percent heavier than a regular club as fast as he could, and then swing one 20 percent lighter as fast as he could.

He and Rickie Fowler played a lot of rounds together during the offseason. Fowler said he could immediately tell that Mickelson’s speed was better.

“I think he’s excited to be hitting it past me at times, where last year, that wasn’t the case,” Fowler said. “He’ll admit that.”

With his strength and speed back, Mickelson assumed he would start this year well.

He stumbled through the stops in California and Arizona where he typically has done well, missing cuts in two of his first three events.

He bounced back and has made four consecutive cuts, including back-to-back rounds of 66 and 67 in Houston. They were his lowest consecutive scores this year.

Mickelson lost his opportunity to win his 43rd PGA tournament with a 75-71 finish. But his 9-under total was his second-lowest this season.

“It was a great feeling being in contention heading into the weekend in Houston, and that was actually important for me,” he said. “I didn’t perform on the weekend the way I wanted to, but it was big for me to feel that nervousness again and to see how close I was.”

Now, Mickelson is walking grounds where he rarely feels nervous.

It’s a much different feeling than what Mickelson said he experienced last year, when he simply didn’t have enough time to prepare for Thursday’s opening round.

As he does every year, Mickelson talked Tuesday about how rejuvenated he feels driving down Magnolia Lane.

He wasn’t as bubbly as he has been in the past, but it was obvious that Mickelson seems happy at the intersection of the improvement in his game and the venue.

He wants that fourth green jacket.

“Winning this tournament, being a part of this championship, coming here every year to compete and try to add to that, is the greatest thing,” he said. “It’s what you think about in the offseason when you’re putting in the work in the gym at 5:30 in the morning. You think about the Masters and what you’re doing it for. This is what gives us the motivation.