By Jonathan Wall, PGATOUR.COM Equipment Insider

Even though he came up short in his bid to secure PGA TOUR win No. 2, Charlie Beljan's first week with Cleveland's 588 MT irons was a success. Like a number of Cleveland staffers, Beljan switched his long irons (2, 3 and 4) to the new game-improvement MT line at the Northern Trust Open.

"I don’t play a 3-wood anymore," Beljan said. "I use the 2-, 3- and 4-irons of the 588 MT. You get the same feel as a solid iron with a much higher trajectory, and I’m getting a couple of extra yards, too."

The irons are geared towards higher handicappers, but a number of players -- including Keegan Bradley, Graeme McDowell and Vijay Singh -- have gone with MT long irons due to the club's ease of use and higher trajectory.

Mickelson goes back to Odyssey Versa: Phil Mickelson has worked with two different putters over the first month-plus of the season. After opening the year with a Odyssey's new Versa putter at the Humana Challenge in partnership with the Clinton Foundation, Mickelson went back to his Odyssey Black Series Tour Design #9 the following week. The 41-time PGA TOUR winner decided to make another change at the Northern Trust Open, putting the Versa #9 WBW (white-black-white) back in the bag.

Haas puts new 2013 Titleist Pro V1x in play: Switching golf balls early in the season can be a tricky proposition -- especially when you're coming off consecutive top-10 finishes. But after putting the new 2013 Titleist Pro V1x to the test during a Tuesday practice round at Riviera, Bill Haas moved out of the old Pro V1x model and into the latest version. The switch produced a tie for third, his third straight top 10 of the season.  

Van Pelt switches to TaylorMade R1: Bo Van Pelt put a new TaylorMade R1 driver in play after comparison testing showed a boost in ball speed, total distance and a tighter dispersion compared to his RBZ Tour.

Bae goes with Callaway RAZR Fit Xtreme: Sang Moon Bae became the latest Callaway staffer to switch to RAZR Fit Xtreme at the Northern Trust Open. Callaway Tour reps worked with Bae to move him from Legacy driver to a 9.5-degree (actual loft 9.2 degrees with a 1-gram weight in the toe and 14-gram weight in the heel) RAZR Fit Xtreme. With the new driver his launch went from an average of 11.5 degrees to 10.75 degrees and spin rate dropped from 2800-2900rpm to 2350-2450rpm. He was also turning the ball over consistently.

Sutherland tweaks Ping G25 3-wood: Less than a week after Kevin Sutherland put a new Fujikura 8.0 Speeder shaft (tipped 1 inch) in his 15-degree Ping G25 3-wood at the AT&T Pebble Beach National Pro-Am, he arrived at Riviera looking to reduce spin. Instead of switching shafts or tipping his Fujikua an extra half-inch, Ping's Tour reps decided to take three-quarter degree of loft off the club. 

Jim Furyk adds Callaway X Hot Pro hybrid: Jim Furyk went with a new a Callaway X Hot Pro (20-degree) at the Northern Trust Open. He noted that he really liked the higher ball flight and consistent distance control.

Divots: Graeme McDowell put a Cleveland 588 MT 4-iron and 5-iron in the bag. ... Jeff Maggert made a loft adjustment to his 13.5-degree Ping G25 3-wood, adding a half-degree to get a higher trajectory. ... Stewart Cink opened the season with a TaylorMade R11S but switched to R1 at the Northern Trust Open after significant progress and effort with testing. ... Looking to solve a yardage gap at Riviera, William McGirt added a TaylorMade RBZ Stage 2 (17-degree) fairway wood. ... Arron Oberholser went with a new Ping Scottsdale TR Shea putter.

John Merrick, who went to UCLA, made the Northern Trust Open his first PGA TOUR win. (How/Getty Images)

By Jonathan Wall, PGATOUR.COM Equipment Insider

John Merrick realized his dream on Sunday at the Northern Trust Open, defeating Charlie Beljan on the second playoff hole to capture his first PGA TOUR victory. The UCLA golf product, who grew up attending the tournament as a kid, used a full bag of Titleist clubs, as well as the new 2013 ProV1x ball, to secure the win.

Fairway wood: Titleist 913F (13.5 degrees) with an Aldila NV85 X shaft

Hybrid: Titleist 913H (19 degrees) with an Aldila NV105 shaft

By Jonathan Wall, PGATOUR.COM Equipment Insider

Dustin Johnson has put new woods, irons and wedges in the bag over the years, but through all the changes there has been one club that has managed to weather the equipment storm: a Titleist Scotty Cameron Newport 2 prototype putter.

Over the last few seasons, Johnson has worked with a number of putters, including a TaylorMade prototype Ghost Itsy Bitsy Spider, Ghost prototype, and an all-black, prototype Scotty Cameron for Titleist Newport known as a "Jetsetter". But he's always gone back to the Newport 2 prototype putter at some point.

On Wednesday at the Northern Trust Open, Golf Channel cameras caught Johnson on the practice putting green working with another new putter — an Odyssey Versa No. 7 WBW (white/black/white).

Johnson not only spent time working with the putter early in the week, he ended up putting it in play on Thursday. Hoping to get his putting on track, Johnson struggled mightily on Riviera's greens, finishing the day at 5 over.

The putter switch wasn't the only equipment change Johnson made this week. On Monday, the seven-time PGA TOUR winner shelved his RocketBladez Tour irons for his old set of TaylorMade Tour Preferred Forged MBs.

By Jonathan Wall, PGATOUR.COM Equipment Insider

PACIFIC PALISADES, Calif. -- When TaylorMade staffers tee it up Thursday at the Northern Trust Open, they'll do so with new R1 golf bags that coincide with the R1 driver campaign that launched this week at Riviera.

While the orange and black bags will certainly stick out from the rest of the pack, the most interesting addition to the new R1 bag is the addition of each TaylorMade staffer's R1 tuning setting on the front panel of the bag.

In an effort to raise awareness regarding the importance of dialing in the proper trajectory and shot shape with the R1, TaylorMade decided to make the R1 setting for each staffer visible to fans.

When TaylorMade released the R1, it noted that 80 percent of players were playing the wrong loft in their driver. By simply having the club tuned properly, the company believes golfers will be able to maximize the performance capabilities of the R1.

To help golfers find the perfect shot shape for their R1, TaylorMade released an R1 Tuning App at the beginning of February that shows users how to correct a slice or hook, alter trajectory and dial in the perfect shape shape in a few simple steps.

Considering the R1 has 168 available combinations, the free app is a nice option if you can't get to certified club fitter.

Phil Mickelson arrived with Riviera with two new Callaway woods in the bag.

By Jonathan Wall, PGATOUR.COM Equipment Insider

PACIFIC PALISADES, Calif. — Two weeks after Phil Mickelson put a Callaway RAZR Fit Xtreme driver in play at the Waste Management Phoenix Open and won by four shots, the four-time major winner arrived at the Northern Trust Open with two new Callaway woods in the bag on Wednesday -- an X Hot Prototype 3-wood and a RAZR Fit Xtreme 5-wood.

Mickelson started working with the X Hot Prototype 3-wood two weeks ago during the second round of the Farmers Insurance Open but went back to his TaylorMade RocketBallz 13-degree (bent to 11.5) shortly thereafter.

After working with the fairway wood over the last few weeks, including on Tuesday at the Ely Callaway Performance Center, he decided to put it back in the bag.

The RAZR Fit Xtreme 5-wood is a brand new addition this week and would replace the Titleist 980F 5-wood Mickelson's been playing of late.

Assuming Mickelson puts both fairway woods in play on Thursday, he would have 13 Callaway clubs in the bag to go along with an Odyssey putter.

By Jonathan Wall, PGATOUR.COM Equipment Insider

PACIFIC PALISADES, Calif. -- Keegan Bradley has been working his way into Cleveland's latest clubs over the last few weeks. After putting two new RTX wedges (52-degree and 58-degree) in the bag at the Phoenix Open, Bradley spent time early in the week at the Northern Trust Open testing a new Cleveland Classic XL Custom driver (9 degrees with a w/ Miyazaki Indigo 61x shaft), 588 MT 3-iron (Miyazaki C Kua 83x hybrid shaft) and a set of 588 TC irons (4-P w/ X-100 .50" over length).

After giving all of the clubs a test run on the course, he decided to put the Classic XL Custom driver and 588 MT 3-iron in the bag. The three-time PGA TOUR winner grew attached to Cleveland's latest driver offering after spending some time with it at home last week in Jupiter, Fla.

Bradley noted the new driver gave him roughly 12-15 additional yards of the tee, and was incredibly accurate.

While the driver may be the most talked-about switch in Bradley's bag this week, the 588 MT 3-iron is likely the club to keep an eye on going forward.

Released late last year during PGA TOUR Qualifying School, Cleveland's Golf Director of Tour Operation Rob Waters, said eight players put at least one 588 MT iron in the bag immediately. Since then, 90 percent of Cleveland staffers have put one 588 MT iron in play, with 50 percent adding at least two 588 MT irons — including Graeme McDowell, who put a 4- and 5-iron in the bag at Riviera.

Bradley told Waters after a practice session that the iron gave him the ability to, among other things, execute a high cut, a shot he hadn't been able to hit consistently with a 3-iron.

Bradley also considered putting the 588 TC irons in play, but opted to wait a couple weeks and test the clubs out at home.