Head to head · 2026 pitching

Zack Kelly vs Mark Leiter Jr.

So far in 2026 Mark Leiter Jr. has been worth 0.6 more 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.

Zack Kelly BOS

Mark Leiter Jr.ATH

2026 pitching, season in progress. The stronger figure in each row is highlighted — for ERA, FIP, WHIP and walks that is the lower one.
Statistic	Zack Kelly	Mark Leiter Jr.
G	17	36
GS	0	0
IP	16.1	33.2
W	0	0
SO	14	38
ERA	3.31	4.28
FIP	3.65	2.95
WHIP	1.29	1.31
K/9	7.7	10.2
BB/9	3.9	2.9
FIP−	87	71
WAR	0.2	0.8

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	Zack Kelly	Mark Leiter Jr.
G	115	306
GS	3	15
IP	131.1	386.0
W	8	16
L	8	30
SV	0	13
SO	127	434
BB	58	142
ERA	4.04	4.57
WHIP	1.31	1.33
K/9	8.7	10.1
BB/9	4.0	3.3
HR/9	1.1	1.3
WAR	0.6	2.5

Zack Kelly’s full profile →Mark Leiter Jr.’s full profile →

More head to heads

The same seasons, measured against somebody else.

Zack Kelly vs

Mark Leiter Jr. 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.