FT. WORTH, Texas — For several years, Stewart Cink has used on a belly putter and been one of the most consistent putters on the PGA Tour. But this week at Colonial, Cink has switched to a traditional-length Nike prototype putter, which appears to be almost identical to the putter that Paul Casey uses. The shape of Cink's putter is a heel-toe weighted Anser-style blade, and the milled face of Nike's prototype putter features a series of red ribs. A Nike employee said those ribs will help to reduce skidding on the greens and get the ball rolling faster.Although Cink said Wednesday that he has always practiced with traditional length putters at home, this marks the first time in over four years that he's had one in the bag at a tournament."It feels really solid and it rolls the ball really nice," he said. "I've been practicing hard so it feels pretty comfortable now."At Colonial, I saw Nike prototype putters with five different head shapes that featured the red ribs in the face. Each was heel-shafted; I did not see a high-MOI Nike prototype putter with the red ribs in the face. It is important to note that prototype golf clubs are built for testing purposes and to allow manufacturers to get feedback from players. Companies want to know which features players like and what changes the pros feel should be made. Not all prototypes become clubs you can eventually buy. However, the prototype putters at Colonial had a lot more cosmetic detail than the putter Casey put into his bag last August at the Barclays Championship. That might suggest Nike is close to completing the development work and may release some new putters fairly soon.Stay in the know by following David Dusek on Twitter.