Legislators in Massachusetts have released a proposed congressional map that would eliminate retiring Rep. John Olver’s (D-Mass.) seat and could force a tough decision by the delegation’s newest member.

The new map shifts the state’s Western districts further west in order to eliminate Olver’s district, as expected. But perhaps more interesting, it puts Reps. Bill Keating (D) and Stephen Lynch (D) into the same district south of Boston, while creating a new Cape Cod district where there is no incumbent.

Massachusetts Reps. Barney Frank (D), left, and Stephen Lynch (D), third from left. (Katherine Frey/THE WASHINGTON POST)

The move from the state’s line-drawers is particularly interesting given Lynch’s opposition to the health care bill that passed in 2009. Some had speculated that he may pay a political price in redistricting; he now faces the prospect of a primary against a fellow member.

The delegation has five members’ homes huddled in and around Boston, but map-makers only made an effort to draw Boston-area districts for four of them, leaving the Cape Cod seat open.

Massachusetts lost one seat in the latest round of reapportionment, and with the state having 10 Democratic members of Congress, the question has been which one would be forced out in the once-a-decade redistricting process.

We thought Olver solved that problem by announcing recently that he won’t seek reelection. The new map effectively gives much of his Western Massachusetts 1st district to Rep. Richard Neal, while combining the rest of Neal’s 2nd district with Rep. Jim McGovern’s Worcester-based 3rd district.

But even with that mystery solved, the drawing together of Keating and Lynch provides some degree of uncertainty and could lead to yet another matchup between incumbents.

Regardless of what happens with Keating and Lynch, though, the state’s House delegation is likely to remain all-Democratic. The current map has featured virtually no competitive races for the last decade.