Whenever pitchers change teams, we immediately analyze the park and league fit for the pitcher in question. And that's understandable, as those are big factors in how he might perform for the upcoming season.
However, when a top-level defender changes teams, the baseball community talks less about his potential impact on his new pitcher teammates .
Three hurlers stand to benefit a great deal based on circumstances that changed this past offseason. Let's look at them now:
Acquisition: Angels trade for Andrelton Simmons
Top beneficiary: Garrett Richards
Richards probably doesn't get enough credit for his 2015 season. He came in off the knee injury that cut his breakout 2014 short and was expected to miss upwards of a month at the outset. Instead, he didn't miss any time and took 32 turns through the rotation. He wasn't nearly as good as he was in 2014, but regression was expected, and his prior knee injury serves somewhat as a mitigating factor. He still managed an above-average 207 1/3 innings of work, a career-high.
Erick Aybar is a capable MLB shortstop who has ranged from a bit below average to well above in his seven full major league seasons, but he doesn't hold a candle to Simmons - a transcendent defender by any measure. Going by Fangraphs UZR, Simmons has three of the top six defensive seasons by a shortstop in the past decade.
That kind of defensive wizardry is going to help the entire staff because even the flyballiest (new word!) pitchers are going to get their share of ground balls. Richards' teammate Hector Santiago was the flyballiest guy in the Majors last year and still registered a 30-percent ground-ball rate. But Richards is unquestionably the prime beneficiary from the Simmons' acquisition. His 55-percent ground-ball rate was sixth-highest last year, and he's reached as high as 58 percent, back in 2013.
With Aybar at short last year, Richards allowed a career-high .280 opponents' average on grounders to the left side, up from an unbelievable .127 in 2014 -- Aybar's second-best UZR season ever. Coming into the season, batters had hit just .196 on ground balls to the left side of the infield, so the .280 really stands out. On balls up the middle and to the right, batters hit only .210 off Richards, so that left side was a major sore spot.
Richards unquestionably has the stuff to regain his 2014 strikeout rate of 24 percent after dipping to 20 percent last year. Pair that with his ground-ball rate and Simmons at short, and you can see how Richards has a chance to replicate his stellar stat-line from '14 (2.61 ERA, 1.04 WHIP).

Acquisition: Padres sign Alexei Ramirez
Top beneficiary: Andrew Cashner
While he only threw 123 1/3 innings, Cashner inspired excitement during a 2014 season in which he posted a 2.55 ERA and a 1.13 WHIP with wicked stuff that had many thinking he could add strikeouts to those gaudy ratios. Well, he added whiffs with a career-high 165 (and a 21 percent K rate that was his best as a starter), but the ratios (4.34 ERA, 1.44 WHIP) regressed a great deal.
Last year's dropoff was in large part due to a .330 BABIP that ranked fifth-worst among qualified starters. Teammate Tyson Ross wasn't far behind at .320 (eighth-highest), and the trio of shortstops who got the bulk of the time for the Padres -- Alexi Amarista, Jedd Gyorko, and Clint Barmes -- were a major reason why.
Enter Ramirez. He isn't coming off his best year -- in fact, 2015 was his worst by the metrics, but he was still better than both Barmes and Gyorko by a wide margin, and they played 51 percent of San Diego's shortstop innings. Prior to 2015, Ramirez had five-well-above-average seasons and one right at average.
Even if Cashner doesn't quite get back to the .275 BABIP he had from 2013-14, the addition of Ramirez should help him cut a big chunk off that higher-than-normal .330 mark from last year.

Acquisition: Royals sign Ian Kennedy
Top beneficiary: Kennedy (from outfield defense)
When Kennedy was traded to San Diego at the Trade Deadline in 2013, many assumed Petco Park would fix his woes and help him regain the 2011 form that resulted in 222 innings of a 2.88 ERA and a top-5 finish in NL Cy Young Award voting. However, his 3.97 ERA as a Padre was actually a few ticks worse than his 3.82 mark with the D-backs. His fly-ball-heavy approach was supposed to be right at home in San Diego, but his 1.7 HR/9 rate from last year represents his career-worst.

Some of those struggles can be attributed to Petco Park becoming less pitcher friendly and, of course, some of it was just poor pitching by Kennedy. But another major factor was the subpar outfield defense the Padres constructed last year. And it wasn't a surprise. Even those who bought in on the Padres' big offseason acknowledged that a Justin Upton-Wil Myers-Matt Kemp outfield was going to be less than elite, to put it lightly.
Myers needed only 298 innings in center to be the fourth-worst by UZR (-8.7), and if you use the UZR/150 (or per 150 games) to check the pace, he was quite easily the worst at -42.5. Meanwhile, Kemp was easily the worst right fielder with a -17.2 UZR.
Given these outfield shortcomings, it's no surprise that Kennedy had the sixth-highest OPS on fly balls and line drives that weren't homers (so outs, 1B, 2B, and 3B) at .956.
By team, the Padres were 28th (or third-worst) at .885, while Kennedy's new Kansas City club was sixth best at .773.
Generally speaking, BABIPs are supposed to be lower for fly-ball pitchers like Kennedy compared to their ground-ball counterparts, yet Kennedy's .304 BABIP since 2012 is eighth-highest in the game. It's tough to make a bigger jump in outfield defense quality than going from the 2015 Padres to the '16 Royals. Expect Kennedy's stats to reflect just that.
A version of this article also appeared at FanGraphs.com.