We are planning a trip to California to see the SanFrancicsco Giants. Can you recommend a hotel that is walkable to the stadium?

Any of the hotels in the Moscone Center or even Union Sq areas are walkable to the stadium.

The closest hotel is probably the Courtyard on 2nd and Folsom (close, but in a business, not tourist, area). Heading along the waterfront, the closest hotels (about a mile+) are the Harbor Court, Vitale and Hyatt Regency, all in a great location, near restaurants, the water, Ferry Building, etc. In another direction, but probably equidistant, are the Moscone Center hotels J62 refers to - the Westin Market Street, W, Marriott on 4th St., etc. The Union Square hotels are a bit farther away, but still walking distance (a long walk).

Are these areas safe if we had to walk from the stadium back to the hotel at night? Thanks.

In order, if I were walking after a game, I'd choose the waterfront hotels first, the Moscone area hotels second and the Courtyard third. There will be plenty of people walking in all directions from the game, but you do have to walk through a less desirable area to get to the Moscone hotels (probably deserted at that hour, though, except for game-goers), and the Courtyard, as I said, is in a business district, which means it is definitely deserted (not inherently dangerous, just deserted). We used to have a monthly parking space just a couple of blocks from the Courtyard (closer to AT&T) and walked back all the time without any problem.

There is also lots of post game transportation to Market St.--Moscone/Union Square area. Most game goers either walk or take public transportation--the ballpark was planned with this in mind. You will not be the only people walking up 3rd to Market after the game.