Kevin Boothe started all 16 games last season at left guard and wants to return — he has spent the past six years with the Giants — and the Giants want him back. Thus far, though, the contract offer is not enough to keep Boothe from hitting unrestricted free agency and, on March 12, the open market. “We’ve had positive conversations on Boothe,’’ his agent, Joel Segal, told The Post. If Boothe, 29, receives a better deal elsewhere, the Giants will have to scramble to replace him, as there isn’t a proven guard currently on the scene. There’s Selvish Capers and Jim Cordle on the roster and also Brandon Mosley, a 2012 fourth-round draft pick from Auburn who spent his entire rookie season on injured reserve. * Former Eagles DT Cullen Jenkins yesterday wrapped up his visit with the Giants. He will visit other teams before deciding on a landing spot. ... David Carr has been Eli Manning’s backup four of the past five years — Sage Rosenfels occupied that role in 2010 — but his tour of duty with the Giants is likely at an end. Carr, 33, will hit the open market and the Giants have already signed 27-year old Curtis Painter as a possible replacement. One likely destination for Carr? Tampa Bay. Former Giants assistant Mike Sullivan is the offensive coordinator for the Buccaneers. Carr wouldn’t mind seeing if he can compete for a starting job. * The release of DE John Abraham by the Falcons swings the door wide open for Osi Umenyiora, an unrestricted free agent looking for a new team. Umenyiora lives in Atlanta.