The A's and free agent Shawn Kelley have mutal interest in the reliever returning to Oakland, sources tell NBC Sports Bay Area.

Kelley, 34, has also drawn interest from three or four other teams, according to a source, who confirmed he will not retire despite considering it late last season.

Kelley played a major role in the A's bullpen the final two months of the season, compiling a 2.16 ERA and 0.78 WHIP with 18 strikeouts in 16 2/3 innings. For the season, he went 2-0 with a 2.94 ERA and 0.90 WHIP between Washington and Oakland.

The veteran right-hander loved his time with the A's, fitting in almost immediately with the rest of the clubhouse.

The A's have already brought back reliever Fernando Rodney for next season, picking up his $5.25 million option last week. Closer Blake Treinen will almost definitely be back as well, along with setup men Lou Trivino, J.B. Wendelken, and Ryan Buchter.

If the A's can come to terms with Kelley, the bullpen will once again be one of the best in baseball.