Last season, Thatcher was dealt from the Padres to the D-backs hours before the July 31 non-waiver Trade Deadline. So what was his reaction to Saturday's move?
"I was surprised," Thatcher said. "I kinda assumed the same thing [as last year] would happen again, so I'm surprised they traded this early before the Deadline, but the sooner I get over here, the better."
Thatcher appeared in 37 games out of the bullpen for Arizona, posting a 2.63 ERA and an 8.33 strikeout-to-walk ratio. He has not walked a batter since April 29 and has only given up two hits since June 8.
The 32-year-old has been tough on lefties, allowing them to hit just .221 against him in his career. This season, left-handed hitters (.241) have posted similar numbers to right-handed hitters (.256).
"He's funky, he's tough to pick up, he makes left-handers very uncomfortable and he's also capable against a righty," Angels general manager Jerry Dipoto said. "He's not a guy who has to be a situational, one-on-one left-hander."
Dipoto said the Angels liked Thatcher's ability to throw strikes, limit walks and strand inherited runners. Thatcher has issued just three walks all season, thrown 72.4 percent of his pitches for strikes and allowed only eight of 37 inherited runners to score.
"When you're looking to clean up that inning with runners on base and get the key out with a left-handed hitter, it's something we've been missing all year long," Dipoto said. "We just haven't had it.
"Joe Thatcher is our shot at an answer."
The Angels bullpen has been the primary focus of Dipoto in the last eight days, orchestrating three trades for relief pitchers. He acquired Jason Grilli on June 27 and Rich Hill on Tuesday. Hill was designated for assignment Saturday to make room for Thatcher.
But Saturday's move could be the last for the Angels, whom many were anticipating to be big Deadline players.
"I don't know how much more tweaking we'll need to do," Dipoto said. "We're not anticipating making a move in any other [non-bullpen] area."
Manager Mike Scioscia said Thatcher would primarily be used as a left-handed specialist but could absorb more innings later.
"We're trying to get some depth and balance in both sides of our 'pen and it keeps evolving and I think we are making strides and getting better down there," Scioscia said. "This will be one big piece that will definitely take the load off some guys that have been pitching a lot and that's a concern, too."
The Angels also added outfielder Tony Campana in the trade that sent outfielder Zach Borenstein and right-hander Joey Krehbiel to Arizona. Campana, 28, has spent most of the season at Triple-A and was optioned to Salt Lake on Saturday.
The D-backs began the day with the worst record in baseball (36-53) and 13 1/2 games out of first place in the National League West.
"Come to a winning ballclub and be in a pennant race, that's what we all play for, so it's exciting," Thatcher said. "I'm excited to come here and get thrown fire right away and help contribute in any way I can."