The one area the Padres have actually addressed a good bit this offseason has been their bullpen. While losing Josh Hader is considerable, the Padres have added a pair of relievers in Yuki Matsui and Woo-Suk Go that should be able to fill the void in a solid manner at the back of the bullpen.
With their starting rotation still in a VERY speculative state, however, it would be very wise for the Padres to continue to build on that bullpen depth. Doing so would protect against any issues that Yu Darvish or Joe Musgrove might have, as well as cover innings if the new additions to the rotation don't work out. Given that the Padres are operating on a tight budget and they already added Go and Matsui, going after the top available relievers probably isn't in the cards. One name that could be a great fit is former Astros reliever Phil Maton.
While there are available relievers with more upside like Robert Stephenson and Hector Neris, those guys are going to be pricey and Maton could be perfect for what the Padres actually need as a reliable 6th/7th inning guy that just gets the job done. Maton doesn't throw hard and gives up more walks than one would like, but he gets strikeouts at a nice clip and has consistently gave the Astros tons of relief appearances while maintaining ERAs in the 3s over the couple of years.
For a team that just needs to be able to find ways to navigate tough games, Maton is an ideal target. The depth and workhorse innings he would provide to the Padres' bullpen would allow them to safely pull starters relatively quickly if things start going south or if innings need to be managed without punting on games entirely. He isn't the sexiest pick, but he should be affordable and is what the Padres need right now.