The Chargers and McKinnie remained in contract discussions as of Wednesday night.
He has also maintained dialogue with the Ravens, but has no offer from the defending Super Bowl champions.
When asked how his visit is going so far, McKinnie replied via a text message: "It's cool."
In a subsequent text after the contract discussions started, McKinnie said: "It's nice out here, nothing final yet."
McKinnie remained in San Diego overnight for his two-day visit and took a physical and met with coaches Wednesday after a dinner with coaches and executives Tuesday night.
The workout for the Dolphins "went pretty good," McKinnie said.
Although the Ravens haven't made an offer for McKinnie to return, they haven't entirely closed the door on potentially bringing him back.
McKinnie, 33, is an unrestricted free agent who started every game in the playoffs after being replaced at left tackle during the regular season by Michael Oher.
The 6-foot-8, 354-pound New Jersey native has been working out regularly in South Florida. McKinnie has battled conditioning and weight issues in the past.
McKinnie was contacted by the Chicago Bears when free agency started, but they quickly reached a deal with former New Orleans Saints and Towson offensive tackle Jermon Bushrod as their new left tackle.
During the playoffs, McKinnie excelled and drew praise from Ravens coach John Harbaugh for stonewalling several top pass rushers during victories over the Indianapolis Colts, Denver Broncos, New England Patriots and the San Francisco 49ers to win the Vince Lombardi trophy.
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