Baseball mechanisms
A field guide to recurring concepts Upon Review uses to make games easier to read.
Pitching
Pitch sequencing
How one pitch changes the hitter's expectation and decision space for the next.
Chase creation
How pitchers earn swings at pitches that finish outside the strike zone.
Whiff generation
How pitchers create empty swings rather than merely weak contact.
Contact management
How pitchers and defenses limit the damage of contact when hitters do put the ball in play.
Leverage and pitching changes
Bullpen sequencing
How the order and timing of relievers shape the matchups a team must navigate late in a game.
Inherited-runner leverage
Why a reliever entering with runners already aboard can face a larger task than the inning line eventually shows.
Base-out pressure
How the combination of runners and outs changes the value, risk, and urgency of each decision.
Times-through-the-order pressure
How repeated looks at a starting pitcher change the tradeoff between leaving him in and moving to the bullpen.
Hitters, matchups, and pressure
Platoon leverage
How hitter-pitcher handedness influences lineup choices, pinch hitting, and bullpen matchups.
First-pitch aggression
How hitters use the first pitch to attack predictable strikes or force pitchers away from comfortable opening patterns.
Two-strike approach
How hitters and pitchers change priorities once the plate appearance reaches two strikes.
Baserunning pressure
How runners create value by threatening advancement, steals, extra bases, or defensive mistakes.