The Detroit Lions are down to two.

Center Travis Swanson, the Lions' third-round pick in the draft, has signed his contract according to a post on his Instagram account. This now leaves two rookies -- Eric Ebron and Kyle Van Noy -- still unsigned.

Terms were not disclosed in Swanson's deal, but last season's No. 76 pick was Keenan Allen, from San Diego.

Allen signed a four-year deal worth about $2.8 million, including a $613,800 signing bonus and a $40,000 workout bonus that would be spread over the final three seasons of his deal. The only guaranteed portion of Allen's deal was his singing bonus. His workout bonus is $10,000 in 2015, $15,000 in 2015 and $15,000 in 2016.

Based on history, including bonuses and the typical bump in base salary from year-to-year, Swanson's deal could be worth about $3 million.