MLB.com reporter Paul Casella is filling in for this edition of Rhett Bollinger¡¯s Angels Beat newsletter. To read the full newsletter, click here. And subscribe to get it regularly in your inbox.

On the surface, the Angels¡¯ addition of right-handed reliever Robert Stephenson?may not seem like a bullpen-altering splash.

After all, Stephenson -- who signed a three-year, $33 million deal -- is a soon-to-be 31-year-old right-hander with a 4.64 career ERA over eight big league seasons, all while playing for four teams.

But now, let¡¯s zero in only on the current version of Stephenson. You know, the guy who posted a 2.35 ERA over 42 appearances following his June 2 trade to the Rays last season.

That success wasn¡¯t just the result of a small sample size or a change of scenery. It came about as a result of a completely revamped approach from Stephenson.

The biggest change Stephenson made was altering the release point on his slider. It sounds simple, but it essentially turned the pitch into a completely new offering -- and an incredibly effective one at that.

By tweaking his mechanics, the pitch is considerably faster and has a much tighter break, essentially making it a cutter -- though Stephenson still refers to the pitch as his slider. Whatever it is, the new version averaged 88.7 mph, well above the previous 84.8 mph average on his slider.

That¡¯s a pretty significant increase for what is by far Stephenson¡¯s most-used pitch. He threw his ¡°cutter¡± 71.6% of the time from July onward.

And regardless of whether Stephenson truly discarded his slider in favor of a cutter or simply tightened up a pitch that was already a cutter, it¡¯s hard to argue with the results.

Opposing batters hit just .101 (8-for-79) with 42 strikeouts against Stephenson's cutter. He had a 59.9% whiff rate with the pitch -- a sizable jump from the 41.8% whiff rate he registered with his old slider.

¡°Just making a little adjustment on how I release [the slider] helped add some velo to it,¡± Stephenson said. ¡°I think that helped a ton on just putting the pitch in the zone more often and getting more swing and miss on it. Moving forward, I feel like that¡¯s sustainable because it¡¯s a better version of that pitch.¡±

Relying heavily on that pitch, Stephenson went from posting a 5.14 ERA in his 18 outings with the Pirates to becoming one of the most dominant relievers in the game with the Rays.

Stephenson not only put up a 2.35 ERA over 42 appearances with Tampa Bay, but his strikeout numbers skyrocketed. His strikeout rate went from 28% with the Pirates to 43% with the Rays.

From July onwards, Stephenson struck out 45% of the batters he faced. Of the 380 pitchers who faced at least 100 batters during that span, nobody had a higher strikeout rate than Stephenson.

"One of the things you look for from a player, especially from a scouting standpoint and just tracking a player over the course of time, is improvement,¡± Angels general manager Perry Minasian said. ¡°He went to Tampa last year and was one of the best, if not the best, reliever in baseball over those 40 innings.¡±

Armed with his elite newfound cutter, Stephenson will undoubtedly be one of the top high-leverage options in an Angels bullpen that ranked 26th with a 4.88 ERA last season. And while incumbent closer Carlos Est¨¦vez was a first-time All-Star last season, he stumbled to a 6.59 ERA in 27 second-half appearances after his remarkable 1.80 ERA in the first half.

¡°We had a hard time in the sixth, seventh, eighth inning,¡± Minasian said. ¡°For us to win more games, and especially compete, we have to be better in those middle innings. Adding a Stephenson, you try to push as many guys as you can down the pecking order. Stephenson gives us another high-leverage guy where [manager Ron Washington] can use him where he wants to and more depth in the bullpen, which we felt like was needed."