Head to head · 2026 pitching

Isaac Mattson vs Juan Mejia

In 2026 the two have been worth the same 0.5 wins. Both lines are computed from play-by-play on the same constants, so they are measured the same way rather than quoted from two sources.

Isaac Mattson PIT

Juan Mejia COL

2026 pitching. The stronger figure in each row is highlighted — for ERA, FIP, WHIP and walks that is the lower one.
Statistic	Isaac Mattson	Juan Mejia
G	38	65
GS	0	1
IP	38.2	70.0
W	0	4
SO	36	66
ERA	5.35	5.27
FIP	3.72	4.17
WHIP	1.60	1.69
K/9	8.4	8.5
BB/9	4.2	5.1
FIP−	89	100
WAR	0.5	0.5

Career

Totalled over the seasons published here, which is not the same as a whole career: a player who debuted before 2015 begins at 2015, not at his real first game.

Career pitching totals. ERA, WHIP and the per-nine rates are recomputed from the components rather than averaged; FIP needs each season’s own constant and is left to the table above.
Statistic	Isaac Mattson	Juan Mejia
G	89	120
GS	0	1
IP	96.0	131.1
W	3	6
L	3	8
SV	0	5
SO	90	134
BB	47	65
ERA	3.94	4.66
WHIP	1.38	1.48
K/9	8.4	9.2
BB/9	4.4	4.5
HR/9	0.7	0.8
WAR	1.1	1.4

Isaac Mattson’s full profile →Juan Mejia’s full profile →

More head to heads

The same seasons, measured against somebody else.

Isaac Mattson vs

Juan Mejia vs

How these are computed

FIP uses the constant solved from this season’s own runs, and FIP− is park-adjusted against the same league. dbWAR is our own open implementation — not fWAR or bWAR — and the full derivation, including its simplifications, is on the methodology page. To put these two beside a third, the comparison page takes up to four.