With 10 days until free agency, the Patriots still don’t know for sure who will protect Tom Brady’s blind side. Nate Solder, who has no plans to retire, is far and away the best left tackle on the market, and he is one of the best at his position to hit free agency over the past few years. Because of that, there’s a belief that he’ll receive offers north of $12 million annually, according to sources. The Patriots’ second option would involve either LaAdrian Waddle or Cameron Fleming, or perhaps a competition among the rotational starters, if they lose Solder. There’s no denying Solder’s preference is to return to the Patriots, but the team shouldn’t expect the same type of hometown discount as his most recent two-year, $20.062 million pact. Yet, as a significant factor in Solder’s decision to take that deal, the Patriots inserted a clause that they couldn’t use the franchise tag on him this offseason, which is why Solder will hit the market if the Pats don’t intensify their negotiations in the coming week. So far, the Patriots haven’t made an offer to Solder, according to sources. However, due to the later-than-usual start to free agency, sources around the league last week said many teams didn’t have the standard urgency to talk numbers during the scouting combine. Some of the Patriots’ marquee free agents in recent years — Devin McCourty, Julian Edelman and Dont’a Hightower — re-signed either just before the dawn of free agency or after the market opened, so the delayed start to Solder’s negotiations are typical of their business practices. Barring an aggressive push by the Patriots in the coming week to lock up the seven-year veteran, Solder’s impending contract will be dictated by offers around the league. It’s still not clear if he’ll want two, three or four years, and the percentage of guaranteed money will hinge on the length of the deal.