Restricted free agent Greg Stiemsma is prepared to sign an offer sheet with the Timberwolves, reports The Celtics are unable to match due to salary-cap constraints and have already found a replacement in Jason Collins: “Restricted free agent center Greg Stiemsma has reached an agreement with the Minnesota Timberwolves, according to his agent. Terms were not disclosed, but the Boston Celtics own only the biannual exception ($1.975 million) to match. The Timberwolves’ offer was expected to trump that, meaning Stiemsma is almost certainly bound for Minnesota. Stiemsma received consistent interest from the Timberwolves this summer, meeting with them near the start of free agency and waiting patiently as they sorted out their own cap issues while pursuing front-line players. The Celtics would have three days to match an offer sheet, or they could simply rescind their $1.1 million qualifying offer to allow Stiemsma to sign as an unrestricted free agent.”